diff --git a/...ries/System.Collections.Concurrent/src/System/Collections/Concurrent/PartitionerStatic.cs b/...ries/System.Collections.Concurrent/src/System/Collections/Concurrent/PartitionerStatic.cs
@@ -707,9 +707,9 @@ internal bool GrabChunk(KeyValuePair<long, TSource>[] destArray, int requestedCh
                 internal bool GrabChunk_Single(KeyValuePair<long, TSource>[] destArray, int requestedChunkSize, ref int actualNumElementsGrabbed)
                 {
                     Debug.Assert(_useSingleChunking, "Expected _useSingleChecking to be true");
-                    Debug.Assert(requestedChunkSize == 1, "Got requested chunk size of " + requestedChunkSize + " when single-chunking was on");
-                    Debug.Assert(actualNumElementsGrabbed == 0, "Expected actualNumElementsGrabbed == 0, instead it is " + actualNumElementsGrabbed);
-                    Debug.Assert(destArray.Length == 1, "Expected destArray to be of length 1, instead its length is " + destArray.Length);
+                    Debug.Assert(requestedChunkSize == 1, $"Got requested chunk size of {requestedChunkSize} when single-chunking was on");
+                    Debug.Assert(actualNumElementsGrabbed == 0, $"Expected actualNumElementsGrabbed == 0, instead it is {actualNumElementsGrabbed}");
+                    Debug.Assert(destArray.Length == 1, $"Expected destArray to be of length 1, instead its length is {destArray.Length}");
 
                     lock (_sharedLock)
                     {

diff --git a/...odel.Composition/src/System/ComponentModel/Composition/ReflectionModel/GenericServices.cs b/...odel.Composition/src/System/ComponentModel/Composition/ReflectionModel/GenericServices.cs
@@ -79,7 +79,7 @@ public static string GetGenericName(string originalGenericName, int[] genericPar
             string[] genericFormatArgs = new string[genericArity];
             for (int i = 0; i < genericParametersOrder.Length; i++)
             {
-                genericFormatArgs[genericParametersOrder[i]] = string.Format(CultureInfo.InvariantCulture, "{{{0}}}", i);
+                genericFormatArgs[genericParametersOrder[i]] = $"{{{i}}}";
             }
             return string.Format(CultureInfo.InvariantCulture, originalGenericName, genericFormatArgs);
         }

diff --git a/...braries/System.ComponentModel.TypeConverter/src/System/ComponentModel/Design/CommandID.cs b/...braries/System.ComponentModel.TypeConverter/src/System/ComponentModel/Design/CommandID.cs
@@ -46,6 +46,6 @@ public override bool Equals([NotNullWhen(true)] object? obj)
         /// <summary>
         /// Overrides Object's ToString method.
         /// </summary>
-        public override string ToString() => Guid.ToString() + " : " + ID.ToString(CultureInfo.CurrentCulture);
+        public override string ToString() => $"{Guid} : {ID}";
     }
 }
diff --git a/....ComponentModel.TypeConverter/src/System/ComponentModel/ReflectTypeDescriptionProvider.cs b/....ComponentModel.TypeConverter/src/System/ComponentModel/ReflectTypeDescriptionProvider.cs
@@ -1114,7 +1114,7 @@ internal static Attribute[] ReflectGetAttributes(MemberInfo member)
 #if DEBUG
                     foreach (EventDescriptor dbgEvent in events)
                     {
-                        Debug.Assert(dbgEvent != null, "Holes in event array for type " + type);
+                        Debug.Assert(dbgEvent != null, $"Holes in event array for type {type}");
                     }
 #endif
                     eventCache[type] = events;

diff --git a/...aries/System.Configuration.ConfigurationManager/src/System/Configuration/XmlUtilWriter.cs b/...aries/System.Configuration.ConfigurationManager/src/System/Configuration/XmlUtilWriter.cs
@@ -176,7 +176,7 @@ internal int AppendEntityRef(string entityRef)
 
         internal int AppendCharEntity(char ch)
         {
-            string numberToWrite = ((int)ch).ToString("X", CultureInfo.InvariantCulture);
+            string numberToWrite = ((int)ch).ToString("X");
             Write('&');
             Write('#');
             Write('x');

diff --git a/src/libraries/System.Console/src/System/TermInfo.cs b/src/libraries/System.Console/src/System/TermInfo.cs
@@ -245,9 +245,10 @@ private static bool TryOpen(string filePath, [NotNullWhen(true)] out SafeFileHan
                     return null;
                 }
 
+                Span<char> stackBuffer = stackalloc char[256];
                 SafeFileHandle? fd;
-                if (!TryOpen(directoryPath + "/" + term[0].ToString() + "/" + term, out fd) &&          // /directory/termFirstLetter/term      (Linux)
-                    !TryOpen(directoryPath + "/" + ((int)term[0]).ToString("X") + "/" + term, out fd))  // /directory/termFirstLetterAsHex/term (Mac)
+                if (!TryOpen(string.Create(null, stackBuffer, $"{directoryPath}/{term[0]}/{term}"), out fd) &&       // /directory/termFirstLetter/term      (Linux)
+                    !TryOpen(string.Create(null, stackBuffer, $"{directoryPath}/{(int)term[0]:X}/{term}"), out fd))  // /directory/termFirstLetterAsHex/term (Mac)
                 {
                     return null;
                 }

diff --git a/src/libraries/System.Data.Common/src/System/Data/Common/DbConnectionStringBuilder.cs b/src/libraries/System.Data.Common/src/System/Data/Common/DbConnectionStringBuilder.cs
@@ -242,7 +242,7 @@ public virtual ICollection Values
                 {
                     keylist.MoveNext();
                     values[i] = this[keylist.Current];
-                    Debug.Assert(null != values[i], "null value " + keylist.Current);
+                    Debug.Assert(null != values[i], $"null value {keylist.Current}");
                 }
                 return new ReadOnlyCollection<object>(values);
             }

diff --git a/src/libraries/System.Data.Common/src/System/Data/DataException.cs b/src/libraries/System.Data.Common/src/System/Data/DataException.cs
@@ -649,7 +649,7 @@ public static string UniqueConstraintViolationText(DataColumn[] columns, object[
         public static Exception RangeArgument(int min, int max) => _Argument(SR.Format(SR.Range_Argument, (min).ToString(CultureInfo.InvariantCulture), (max).ToString(CultureInfo.InvariantCulture)));
         public static Exception NullRange() => _Data(SR.Range_NullRange);
         public static Exception NegativeMinimumCapacity() => _Argument(SR.RecordManager_MinimumCapacity);
-        public static Exception ProblematicChars(char charValue) => _Argument(SR.Format(SR.DataStorage_ProblematicChars, "0x" + ((ushort)charValue).ToString("X", CultureInfo.InvariantCulture)));
+        public static Exception ProblematicChars(char charValue) => _Argument(SR.Format(SR.DataStorage_ProblematicChars, $"0x{(ushort)charValue:X}"));
         public static Exception StorageSetFailed() => _Argument(SR.DataStorage_SetInvalidDataType);
 
 

diff --git a/src/libraries/System.Data.Common/src/System/Data/Filter/AggregateNode.cs b/src/libraries/System.Data.Common/src/System/Data/Filter/AggregateNode.cs
@@ -114,7 +114,7 @@ internal override void Bind(DataTable table, List<DataColumn> list)
 
             // add column to the dependency list, do not add duplicate columns
 
-            Debug.Assert(_column != null, "Failed to bind column " + _columnName);
+            Debug.Assert(_column != null, $"Failed to bind column {_columnName}");
 
             int i;
             for (i = 0; i < list.Count; i++)

diff --git a/src/libraries/System.Data.Common/src/System/Data/Filter/FunctionNode.cs b/src/libraries/System.Data.Common/src/System/Data/Filter/FunctionNode.cs
@@ -318,7 +318,7 @@ private object EvalFunction(FunctionId id, object[] argumentValues, DataRow? row
             switch (id)
             {
                 case FunctionId.Abs:
-                    Debug.Assert(_argumentCount == 1, "Invalid argument argumentCount for " + s_funcs[_info]._name + " : " + _argumentCount.ToString(FormatProvider));
+                    Debug.Assert(_argumentCount == 1, $"Invalid argument argumentCount for {s_funcs[_info]._name} : {_argumentCount.ToString(FormatProvider)}");
 
                     storageType = DataStorage.GetStorageType(argumentValues[0].GetType());
                     if (ExpressionNode.IsInteger(storageType))
@@ -329,7 +329,7 @@ private object EvalFunction(FunctionId id, object[] argumentValues, DataRow? row
                     throw ExprException.ArgumentTypeInteger(s_funcs[_info]._name, 1);
 
                 case FunctionId.cBool:
-                    Debug.Assert(_argumentCount == 1, "Invalid argument argumentCount for " + s_funcs[_info]._name + " : " + _argumentCount.ToString(FormatProvider));
+                    Debug.Assert(_argumentCount == 1, $"Invalid argument argumentCount for {s_funcs[_info]._name} : {_argumentCount.ToString(FormatProvider)}");
 
                     storageType = DataStorage.GetStorageType(argumentValues[0].GetType());
                     return storageType switch
@@ -341,26 +341,26 @@ private object EvalFunction(FunctionId id, object[] argumentValues, DataRow? row
                         _ => throw ExprException.DatatypeConvertion(argumentValues[0].GetType(), typeof(bool)),
                     };
                 case FunctionId.cInt:
-                    Debug.Assert(_argumentCount == 1, "Invalid argument argumentCount for " + s_funcs[_info]._name + " : " + _argumentCount.ToString(FormatProvider));
+                    Debug.Assert(_argumentCount == 1, $"Invalid argument argumentCount for {s_funcs[_info]._name} : {_argumentCount.ToString(FormatProvider)}");
                     return Convert.ToInt32(argumentValues[0], FormatProvider);
 
                 case FunctionId.cDate:
-                    Debug.Assert(_argumentCount == 1, "Invalid argument argumentCount for " + s_funcs[_info]._name + " : " + _argumentCount.ToString(FormatProvider));
+                    Debug.Assert(_argumentCount == 1, $"Invalid argument argumentCount for {s_funcs[_info]._name} : {_argumentCount.ToString(FormatProvider)}");
                     return Convert.ToDateTime(argumentValues[0], FormatProvider);
 
                 case FunctionId.cDbl:
-                    Debug.Assert(_argumentCount == 1, "Invalid argument argumentCount for " + s_funcs[_info]._name + " : " + _argumentCount.ToString(FormatProvider));
+                    Debug.Assert(_argumentCount == 1, $"Invalid argument argumentCount for {s_funcs[_info]._name} : {_argumentCount.ToString(FormatProvider)}");
                     return Convert.ToDouble(argumentValues[0], FormatProvider);
 
                 case FunctionId.cStr:
-                    Debug.Assert(_argumentCount == 1, "Invalid argument argumentCount for " + s_funcs[_info]._name + " : " + _argumentCount.ToString(FormatProvider));
+                    Debug.Assert(_argumentCount == 1, $"Invalid argument argumentCount for {s_funcs[_info]._name} : {_argumentCount.ToString(FormatProvider)}");
                     return Convert.ToString(argumentValues[0], FormatProvider)!;
 
                 case FunctionId.Charindex:
-                    Debug.Assert(_argumentCount == 2, "Invalid argument argumentCount for " + s_funcs[_info]._name + " : " + _argumentCount.ToString(FormatProvider));
+                    Debug.Assert(_argumentCount == 2, $"Invalid argument argumentCount for {s_funcs[_info]._name} : {_argumentCount.ToString(FormatProvider)}");
 
-                    Debug.Assert(argumentValues[0] is string, "Invalid argument type for " + s_funcs[_info]._name);
-                    Debug.Assert(argumentValues[1] is string, "Invalid argument type for " + s_funcs[_info]._name);
+                    Debug.Assert(argumentValues[0] is string, $"Invalid argument type for {s_funcs[_info]._name}");
+                    Debug.Assert(argumentValues[1] is string, $"Invalid argument type for {s_funcs[_info]._name}");
 
                     if (DataStorage.IsObjectNull(argumentValues[0]) || DataStorage.IsObjectNull(argumentValues[1]))
                         return DBNull.Value;
@@ -374,7 +374,7 @@ private object EvalFunction(FunctionId id, object[] argumentValues, DataRow? row
                     return ((string)argumentValues[1]).IndexOf((string)argumentValues[0], StringComparison.Ordinal);
 
                 case FunctionId.Iif:
-                    Debug.Assert(_argumentCount == 3, "Invalid argument argumentCount: " + _argumentCount.ToString(FormatProvider));
+                    Debug.Assert(_argumentCount == 3, $"Invalid argument argumentCount: {_argumentCount.ToString(FormatProvider)}");
 
                     object first = _arguments![0].Eval(row, version);
 
@@ -401,8 +401,8 @@ private object EvalFunction(FunctionId id, object[] argumentValues, DataRow? row
                         return argumentValues[0];
 
                 case FunctionId.Len:
-                    Debug.Assert(_argumentCount == 1, "Invalid argument argumentCount for " + s_funcs[_info]._name + " : " + _argumentCount.ToString(FormatProvider));
-                    Debug.Assert((argumentValues[0] is string) || (argumentValues[0] is SqlString), "Invalid argument type for " + s_funcs[_info]._name);
+                    Debug.Assert(_argumentCount == 1, $"Invalid argument argumentCount for {s_funcs[_info]._name} : {_argumentCount.ToString(FormatProvider)}");
+                    Debug.Assert((argumentValues[0] is string) || (argumentValues[0] is SqlString), $"Invalid argument type for {s_funcs[_info]._name}");
 
                     if (argumentValues[0] is SqlString)
                     {
@@ -420,10 +420,10 @@ private object EvalFunction(FunctionId id, object[] argumentValues, DataRow? row
 
 
                 case FunctionId.Substring:
-                    Debug.Assert(_argumentCount == 3, "Invalid argument argumentCount: " + _argumentCount.ToString(FormatProvider));
-                    Debug.Assert((argumentValues[0] is string) || (argumentValues[0] is SqlString), "Invalid first argument " + argumentValues[0].GetType().FullName + " in " + s_funcs[_info]._name);
-                    Debug.Assert(argumentValues[1] is int, "Invalid second argument " + argumentValues[1].GetType().FullName + " in " + s_funcs[_info]._name);
-                    Debug.Assert(argumentValues[2] is int, "Invalid third argument " + argumentValues[2].GetType().FullName + " in " + s_funcs[_info]._name);
+                    Debug.Assert(_argumentCount == 3, $"Invalid argument argumentCount: {_argumentCount.ToString(FormatProvider)}");
+                    Debug.Assert((argumentValues[0] is string) || (argumentValues[0] is SqlString), $"Invalid first argument {argumentValues[0].GetType().FullName} in {s_funcs[_info]._name}");
+                    Debug.Assert(argumentValues[1] is int, $"Invalid second argument {argumentValues[1].GetType().FullName} in {s_funcs[_info]._name}");
+                    Debug.Assert(argumentValues[2] is int, $"Invalid third argument {argumentValues[2].GetType().FullName} in {s_funcs[_info]._name}");
 
                     // work around the differences in .NET and VBA implementation of the Substring function
                     // 1. The <index> Argument is 0-based in .NET, and 1-based in VBA
@@ -462,8 +462,8 @@ private object EvalFunction(FunctionId id, object[] argumentValues, DataRow? row
 
                 case FunctionId.Trim:
                     {
-                        Debug.Assert(_argumentCount == 1, "Invalid argument argumentCount for " + s_funcs[_info]._name + " : " + _argumentCount.ToString(FormatProvider));
-                        Debug.Assert((argumentValues[0] is string) || (argumentValues[0] is SqlString), "Invalid argument type for " + s_funcs[_info]._name);
+                        Debug.Assert(_argumentCount == 1, $"Invalid argument argumentCount for {s_funcs[_info]._name} : {_argumentCount.ToString(FormatProvider)}");
+                        Debug.Assert((argumentValues[0] is string) || (argumentValues[0] is SqlString), $"Invalid argument type for {s_funcs[_info]._name}");
 
                         if (DataStorage.IsObjectNull(argumentValues[0]))
                             return DBNull.Value;

diff --git a/src/libraries/System.Data.Common/src/System/Data/Filter/NameNode.cs b/src/libraries/System.Data.Common/src/System/Data/Filter/NameNode.cs
@@ -58,7 +58,7 @@ internal override void Bind(DataTable table, List<DataColumn> list)
             _found = true;
 
             // add column to the dependency list, do not add duplicate columns
-            Debug.Assert(_column != null, "Failed to bind column " + _name);
+            Debug.Assert(_column != null, $"Failed to bind column {_name}");
 
             int i;
             for (i = 0; i < list.Count; i++)

diff --git a/src/libraries/System.Data.Common/src/System/Data/ForeignKeyConstraint.cs b/src/libraries/System.Data.Common/src/System/Data/ForeignKeyConstraint.cs
@@ -504,7 +504,7 @@ internal void CheckCanClearParentTable(DataTable table)
 
         internal void CheckCanRemoveParentRow(DataRow row)
         {
-            Debug.Assert(Table?.DataSet != null, "Relation " + ConstraintName + " isn't part of a DataSet, so this check shouldn't be happening.");
+            Debug.Assert(Table?.DataSet != null, $"Relation {ConstraintName} isn't part of a DataSet, so this check shouldn't be happening.");
             if (!Table.DataSet.EnforceConstraints)
             {
                 return;
@@ -517,7 +517,7 @@ internal void CheckCanRemoveParentRow(DataRow row)
 
         internal void CheckCascade(DataRow row, DataRowAction action)
         {
-            Debug.Assert(Table?.DataSet != null, "ForeignKeyConstraint " + ConstraintName + " isn't part of a DataSet, so this check shouldn't be happening.");
+            Debug.Assert(Table?.DataSet != null, $"ForeignKeyConstraint {ConstraintName} isn't part of a DataSet, so this check shouldn't be happening.");
 
             if (row._inCascade)
             {

diff --git a/src/libraries/System.Data.Common/src/System/Data/Merger.cs b/src/libraries/System.Data.Common/src/System/Data/Merger.cs
@@ -608,7 +608,7 @@ private void MergeRelation(DataRelation relation)
                 }
                 else
                 {
-                    Debug.Assert(MissingSchemaAction.Error == _missingSchemaAction, "Unexpected value of MissingSchemaAction parameter : " + _missingSchemaAction.ToString());
+                    Debug.Assert(MissingSchemaAction.Error == _missingSchemaAction, $"Unexpected value of MissingSchemaAction parameter : {_missingSchemaAction}");
                     throw ExceptionBuilder.MergeMissingDefinition(relation.RelationName);
                 }
             }

diff --git a/src/libraries/System.Data.Common/src/System/Data/SQLTypes/SQLBinary.cs b/src/libraries/System.Data.Common/src/System/Data/SQLTypes/SQLBinary.cs
@@ -119,8 +119,7 @@ public int Length
         /// <summary>
         /// Returns a string describing a <see cref='SqlBinary'/> object.
         /// </summary>
-        public override string ToString() =>
-            _value is null ? SQLResource.NullString : "SqlBinary(" + _value.Length.ToString(CultureInfo.InvariantCulture) + ")";
+        public override string ToString() => _value is null ? SQLResource.NullString : $"SqlBinary({_value.Length})";
 
         // Unary operators
 

diff --git a/src/libraries/System.Data.Common/src/System/Data/SQLTypes/SQLDecimal.cs b/src/libraries/System.Data.Common/src/System/Data/SQLTypes/SQLDecimal.cs
@@ -1911,7 +1911,7 @@ private bool FGt10_38()
 
         private bool FGt10_38(Span<uint> rglData)
         {
-            Debug.Assert(rglData.Length == 4, "rglData.Length == 4", "Wrong array length: " + rglData.Length.ToString(CultureInfo.InvariantCulture));
+            Debug.Assert(rglData.Length == 4, "rglData.Length == 4", $"Wrong array length: {rglData.Length}");
 
             return rglData[3] >= 0x4b3b4ca8L &&
             ((rglData[3] > 0x4b3b4ca8L) || (rglData[2] > 0x5a86c47aL) ||

diff --git a/src/libraries/System.Data.Common/src/System/Data/XDRSchema.cs b/src/libraries/System.Data.Common/src/System/Data/XDRSchema.cs
@@ -130,7 +130,7 @@ internal void LoadSchema(XmlElement schemaRoot, DataSet ds)
 
         internal bool IsTextOnlyContent(XmlElement node)
         {
-            Debug.Assert(FEqualIdentity(node, Keywords.XDR_ELEMENTTYPE, Keywords.XDRNS), "Invalid node type " + node.LocalName);
+            Debug.Assert(FEqualIdentity(node, Keywords.XDR_ELEMENTTYPE, Keywords.XDRNS), $"Invalid node type {node.LocalName}");
 
             string value = node.GetAttribute(Keywords.CONTENT);
             if (value == null || value.Length == 0)
@@ -282,12 +282,12 @@ private static NameType FindNameType(string name)
                 // Let's check that we realy don't have this name:
                 foreach (NameType nt in s_mapNameTypeXdr)
                 {
-                    Debug.Assert(nt.name != name, "FindNameType('" + name + "') -- failed. Existed name not found");
+                    Debug.Assert(nt.name != name, $"FindNameType('{name}') -- failed. Existed name not found");
                 }
 #endif
                 throw ExceptionBuilder.UndefinedDatatype(name);
             }
-            Debug.Assert(s_mapNameTypeXdr[index].name == name, "FindNameType('" + name + "') -- failed. Wrong name found");
+            Debug.Assert(s_mapNameTypeXdr[index].name == name, $"FindNameType('{name}') -- failed. Wrong name found");
             return s_mapNameTypeXdr[index];
         }
 

diff --git a/src/libraries/System.Data.Common/src/System/Data/XMLSchema.cs b/src/libraries/System.Data.Common/src/System/Data/XMLSchema.cs
@@ -1790,7 +1790,7 @@ public static Type XsdtoClr(string xsdTypeName)
 #if DEBUG
             for (int i = 1; i < s_mapNameTypeXsd.Length; ++i)
             {
-                Debug.Assert((s_mapNameTypeXsd[i - 1].CompareTo(s_mapNameTypeXsd[i].name)) < 0, "incorrect sorting " + s_mapNameTypeXsd[i].name);
+                Debug.Assert((s_mapNameTypeXsd[i - 1].CompareTo(s_mapNameTypeXsd[i].name)) < 0, $"incorrect sorting {s_mapNameTypeXsd[i].name}");
             }
 #endif
             int index = Array.BinarySearch(s_mapNameTypeXsd, xsdTypeName);
@@ -1856,7 +1856,7 @@ private static NameType FindNameType(string name)
 #if DEBUG
             for (int i = 1; i < s_mapNameTypeXsd.Length; ++i)
             {
-                Debug.Assert((s_mapNameTypeXsd[i - 1].CompareTo(s_mapNameTypeXsd[i].name)) < 0, "incorrect sorting " + s_mapNameTypeXsd[i].name);
+                Debug.Assert((s_mapNameTypeXsd[i - 1].CompareTo(s_mapNameTypeXsd[i].name)) < 0, $"incorrect sorting {s_mapNameTypeXsd[i].name}");
             }
 #endif
             int index = Array.BinarySearch(s_mapNameTypeXsd, name);
@@ -1904,7 +1904,7 @@ internal static bool IsXsdType(string name)
 #if DEBUG
             for (int i = 1; i < s_mapNameTypeXsd.Length; ++i)
             {
-                Debug.Assert((s_mapNameTypeXsd[i - 1].CompareTo(s_mapNameTypeXsd[i].name)) < 0, "incorrect sorting " + s_mapNameTypeXsd[i].name);
+                Debug.Assert((s_mapNameTypeXsd[i - 1].CompareTo(s_mapNameTypeXsd[i].name)) < 0, $"incorrect sorting {s_mapNameTypeXsd[i].name}");
             }
 #endif
             int index = Array.BinarySearch(s_mapNameTypeXsd, name);
@@ -1914,12 +1914,12 @@ internal static bool IsXsdType(string name)
                 // Let's check that we realy don't have this name:
                 foreach (NameType nt in s_mapNameTypeXsd)
                 {
-                    Debug.Assert(nt.name != name, "FindNameType('" + name + "') -- failed. Existed name not found");
+                    Debug.Assert(nt.name != name, $"FindNameType('{name}') -- failed. Existed name not found");
                 }
 #endif
                 return false;
             }
-            Debug.Assert(s_mapNameTypeXsd[index].name == name, "FindNameType('" + name + "') -- failed. Wrong name found");
+            Debug.Assert(s_mapNameTypeXsd[index].name == name, $"FindNameType('{name}') -- failed. Wrong name found");
             return true;
         }
 

diff --git a/src/libraries/System.Data.Common/src/System/Data/xmlsaver.cs b/src/libraries/System.Data.Common/src/System/Data/xmlsaver.cs
@@ -1295,7 +1295,7 @@ internal void HandleColumnType(DataColumn col, XmlDocument dc, XmlElement root,
                         {
 #if DEBUG
                             // enzol: TO DO: replace the constructor with IsEqual(XmlElement)
-                            //                        Debug.Assert(col.SimpleType.IsEqual(new SimpleType(elmSimpeType)), "simpleTypes with the same name have to be the same: "+name);
+                            //                        Debug.Assert(col.SimpleType.IsEqual(new SimpleType(elmSimpeType)), $"simpleTypes with the same name have to be the same: {name}");
 #endif
                         }
                     }

diff --git a/src/libraries/System.Data.Common/tests/System/Data/DataSetTest2.cs b/src/libraries/System.Data.Common/tests/System/Data/DataSetTest2.cs
@@ -435,7 +435,7 @@ public void GetXml()
 
             StringBuilder resultXML = new StringBuilder();
 
-            resultXML.Append("<" + ds.DataSetName + "xmlns=\"namespace\">");
+            resultXML.Append($"<{ds.DataSetName}xmlns=\"namespace\">");
 
             resultXML.Append("<Parent>");
             resultXML.Append("<ParentId>1</ParentId>");
@@ -455,7 +455,7 @@ public void GetXml()
             resultXML.Append("<String2>Value5</String2>");
             resultXML.Append("</Parent>");
 
-            resultXML.Append("</" + ds.DataSetName + ">");
+            resultXML.Append($"</{ds.DataSetName}>");
 
             ds.Tables.Add(dt);
             string strXML = ds.GetXml();

diff --git a/src/libraries/System.Data.Odbc/src/System/Data/Odbc/OdbcParameter.cs b/src/libraries/System.Data.Odbc/src/System/Data/Odbc/OdbcParameter.cs
@@ -527,7 +527,7 @@ private int GetParameterSize(object? value, int offset, int ordinal)
                     }
                 }
             }
-            Debug.Assert((0 <= ccb) && (ccb < 0x3fffffff), "GetParameterSize: out of range " + ccb);
+            Debug.Assert((0 <= ccb) && (ccb < 0x3fffffff), $"GetParameterSize: out of range {ccb}");
             return ccb;
         }
 

diff --git a/src/libraries/System.Data.Odbc/tests/TestCommon/DataTestUtility.cs b/src/libraries/System.Data.Odbc/tests/TestCommon/DataTestUtility.cs
@@ -23,12 +23,7 @@ public static bool AreConnStringsSetup()
         // some providers does not support names (Oracle supports up to 30)
         public static string GetUniqueName(string prefix, string escapeLeft, string escapeRight)
         {
-            string uniqueName = string.Format("{0}{1}_{2}_{3}{4}",
-                escapeLeft,
-                prefix,
-                DateTime.Now.Ticks.ToString("X", CultureInfo.InvariantCulture), // up to 8 characters
-                Guid.NewGuid().ToString().Substring(0, 6), // take the first 6 characters only
-                escapeRight);
+            string uniqueName = $"{escapeLeft}{prefix}_{DateTime.Now.Ticks:X}_{Guid.NewGuid().ToString().Substring(0, 6)}{escapeRight}";
             return uniqueName;
         }
 

diff --git a/src/libraries/System.Data.OleDb/src/ColumnBinding.cs b/src/libraries/System.Data.OleDb/src/ColumnBinding.cs
@@ -55,7 +55,7 @@ internal sealed class ColumnBinding
         {
             Debug.Assert(null != rowbinding, "null rowbinding");
             Debug.Assert(null != bindings, "null bindings");
-            Debug.Assert(ODB.SizeOf_tagDBBINDING <= offset, "invalid offset" + offset);
+            Debug.Assert(ODB.SizeOf_tagDBBINDING <= offset, $"invalid offset {offset}");
 
             _dataReader = dataReader;
             _rowbinding = rowbinding;

diff --git a/src/libraries/System.Data.OleDb/src/DbConnectionOptions.cs b/src/libraries/System.Data.OleDb/src/DbConnectionOptions.cs
@@ -844,8 +844,8 @@ private static void ParseComparison(Hashtable parsetable, string connectionStrin
                     string keyname = (string)entry.Key;
                     string? value1 = (string?)entry.Value;
                     string? value2 = (string?)parsetable[keyname];
-                    Debug.Assert(parsetable.Contains(keyname), "ParseInternal code vs. regex mismatch keyname <" + keyname + ">");
-                    Debug.Assert(value1 == value2, "ParseInternal code vs. regex mismatch keyvalue <" + value1 + "> <" + value2 + ">");
+                    Debug.Assert(parsetable.Contains(keyname), $"ParseInternal code vs. regex mismatch keyname <{keyname}>");
+                    Debug.Assert(value1 == value2, $"ParseInternal code vs. regex mismatch keyvalue <{value1}> <{value2}>");
                 }
 
             }
@@ -871,11 +871,11 @@ private static void ParseComparison(Hashtable parsetable, string connectionStrin
                             }
                         }
                     }
-                    Debug.Assert(isEquivalent, "ParseInternal code vs regex message mismatch: <" + msg1 + "> <" + msg2 + ">");
+                    Debug.Assert(isEquivalent, $"ParseInternal code vs regex message mismatch: <{msg1}> <{msg2}>");
                 }
                 else
                 {
-                    Debug.Assert(false, "ParseInternal code vs regex throw mismatch " + f.Message);
+                    Debug.Assert(false, $"ParseInternal code vs regex throw mismatch {f.Message}");
                 }
                 e = null;
             }

diff --git a/src/libraries/System.Data.OleDb/src/DbPropSet.cs b/src/libraries/System.Data.OleDb/src/DbPropSet.cs
@@ -254,7 +254,7 @@ internal void SetPropertySet(int index, Guid propertySet, ItagDBPROP[] propertie
 
                 for (int i = 0; i < properties.Length; ++i)
                 {
-                    Debug.Assert(null != properties[i], "null tagDBPROP " + i.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(null != properties[i], $"null tagDBPROP {i.ToString(CultureInfo.InvariantCulture)}");
                     IntPtr propertyPtr = ADP.IntPtrOffset(propset.rgProperties, i * ODB.SizeOf_tagDBPROP);
                     Marshal.StructureToPtr(properties[i], propertyPtr, false/*deleteold*/);
                 }

diff --git a/src/libraries/System.Data.OleDb/src/OleDbConnection.cs b/src/libraries/System.Data.OleDb/src/OleDbConnection.cs
@@ -235,7 +235,7 @@ public void ResetState()
                             break;
 
                         default: // have to assume everything is okay
-                            Debug.Assert(false, "Unknown 'Connection Status' value " + connectionStatus.ToString("G", CultureInfo.InvariantCulture));
+                            Debug.Assert(false, $"Unknown 'Connection Status' value {connectionStatus.ToString("G", CultureInfo.InvariantCulture)}");
                             break;
                     }
                 }

diff --git a/src/libraries/System.Data.OleDb/src/OleDbDataReader.cs b/src/libraries/System.Data.OleDb/src/OleDbDataReader.cs
@@ -584,7 +584,7 @@ private void BuildSchemaTableInfoTable(int columnCount, IntPtr columnInfos, bool
 #if DEBUG
                 if (AdapterSwitches.DataSchema.TraceVerbose)
                 {
-                    Debug.WriteLine("OleDbDataReader[" + info.ordinal.ToInt64().ToString(CultureInfo.InvariantCulture) + ", " + dbColumnInfo.pwszName + "]=" + dbType.enumOleDbType.ToString() + "," + dbType.dataSourceType + ", " + dbType.wType);
+                    Debug.WriteLine($"OleDbDataReader[{info.ordinal}, {dbColumnInfo.pwszName}]={dbType.enumOleDbType},{dbType.dataSourceType}, {dbType.wType}");
                 }
 #endif
                 rowCount++;
@@ -2108,7 +2108,7 @@ private int AppendSchemaPrimaryKey(Hashtable baseColumnNames, object?[] restrict
 #if DEBUG
                             if (AdapterSwitches.DataSchema.TraceVerbose)
                             {
-                                Debug.WriteLine("PartialKeyColumn detected: <" + name + "> metaindex=" + metaindex);
+                                Debug.WriteLine($"PartialKeyColumn detected: <{name}> metaindex={metaindex}");
                             }
 #endif
                             partialPrimaryKey = true;
@@ -2199,7 +2199,7 @@ private void AppendSchemaUniqueIndexAsKey(Hashtable baseColumnNames, object?[] r
 #if DEBUG
                                         if (AdapterSwitches.DataSchema.TraceVerbose)
                                         {
-                                            Debug.WriteLine("MultipleUniqueIndexes detected: <" + uniqueIndexName + "> <" + indexname + ">");
+                                            Debug.WriteLine($"MultipleUniqueIndexes detected: <{uniqueIndexName}> <{indexname}>");
                                         }
 #endif
                                         uniq = null;
@@ -2211,7 +2211,7 @@ private void AppendSchemaUniqueIndexAsKey(Hashtable baseColumnNames, object?[] r
 #if DEBUG
                                 if (AdapterSwitches.DataSchema.TraceVerbose)
                                 {
-                                    Debug.WriteLine("PartialKeyColumn detected: " + name);
+                                    Debug.WriteLine($"PartialKeyColumn detected: {name}");
                                 }
 #endif
                                 partialPrimaryKey = true;
@@ -2226,7 +2226,7 @@ private void AppendSchemaUniqueIndexAsKey(Hashtable baseColumnNames, object?[] r
 #if DEBUG
                                     if (AdapterSwitches.DataSchema.TraceVerbose)
                                     {
-                                        Debug.WriteLine("PartialUniqueIndexes detected: <" + uniqueIndexName + "> <" + indexname + ">");
+                                        Debug.WriteLine($"PartialUniqueIndexes detected: <{uniqueIndexName}> <{indexname}>");
                                     }
 #endif
                                     uniq = null;
@@ -2247,7 +2247,7 @@ private void AppendSchemaUniqueIndexAsKey(Hashtable baseColumnNames, object?[] r
 #if DEBUG
                         if (AdapterSwitches.DataSchema.TraceVerbose)
                         {
-                            Debug.WriteLine("upgrade single unique index to be a key: <" + uniqueIndexName + ">");
+                            Debug.WriteLine($"upgrade single unique index to be a key: <{uniqueIndexName}>");
                         }
 #endif
                         // upgrade single unique index to be a key
@@ -2498,7 +2498,7 @@ internal void DumpToSchemaTable(UnsafeNativeMethods.IRowset? rowset)
 #if DEBUG
                     if (AdapterSwitches.DataSchema.TraceVerbose)
                     {
-                        Debug.WriteLine("Filtered Column: DBCOLUMN_GUID=DBCOL_SPECIALCOL DBCOLUMN_NAME=" + info.columnName + " DBCOLUMN_KEYCOLUMN=" + info.isKeyColumn);
+                        Debug.WriteLine($"Filtered Column: DBCOLUMN_GUID=DBCOL_SPECIALCOL DBCOLUMN_NAME={info.columnName} DBCOLUMN_KEYCOLUMN={info.isKeyColumn}");
                     }
 #endif
                     info.isHidden = true;
@@ -2509,7 +2509,7 @@ internal void DumpToSchemaTable(UnsafeNativeMethods.IRowset? rowset)
 #if DEBUG
                     if (AdapterSwitches.DataSchema.TraceVerbose)
                     {
-                        Debug.WriteLine("Filtered Column: DBCOLUMN_NUMBER=" + info.ordinal.ToInt64().ToString(CultureInfo.InvariantCulture) + " DBCOLUMN_NAME=" + info.columnName);
+                        Debug.WriteLine($"Filtered Column: DBCOLUMN_NUMBER={info.ordinal} DBCOLUMN_NAME={info.columnName}");
                     }
 #endif
                     info.isHidden = true;
@@ -2520,7 +2520,7 @@ internal void DumpToSchemaTable(UnsafeNativeMethods.IRowset? rowset)
 #if DEBUG
                     if (AdapterSwitches.DataSchema.TraceVerbose)
                     {
-                        Debug.WriteLine("Filtered Column: DBCOLUMN_FLAGS=" + info.flags.ToString("X8", null) + " DBCOLUMN_NAME=" + info.columnName);
+                        Debug.WriteLine($"Filtered Column: DBCOLUMN_FLAGS={info.flags:X8} DBCOLUMN_NAME={info.columnName}");
                     }
 #endif
                     info.isHidden = true;

diff --git a/src/libraries/System.Data.OleDb/src/OleDbStruct.cs b/src/libraries/System.Data.OleDb/src/OleDbStruct.cs
@@ -52,10 +52,10 @@ public override string ToString()
             {
                 builder.Append("pwszDataSourceType =").Append(Marshal.PtrToStringUni(pwszDataSourceType)).Append(Environment.NewLine);
             }
-            builder.Append("\tulParamSize  =" + ulParamSize.ToInt64().ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tdwFlags     =0x" + dwFlags.ToString("X4", CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tPrecision   =" + bPrecision.ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tScale       =" + bScale.ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
+            builder.AppendLine($"\tulParamSize  ={ulParamSize}");
+            builder.AppendLine($"\tdwFlags      =0x{dwFlags:X4}");
+            builder.AppendLine($"\tPrecision    ={bPrecision}");
+            builder.AppendLine($"\tScale        ={bScale}");
             return builder.ToString();
         }
 #endif
@@ -78,12 +78,12 @@ public override string ToString()
             builder.Append("tagDBPARAMBINDINFO").Append(Environment.NewLine);
             if (IntPtr.Zero != pwszDataSourceType)
             {
-                builder.Append("pwszDataSourceType =").Append(Marshal.PtrToStringUni(pwszDataSourceType)).Append(Environment.NewLine);
+                builder.AppendLine($"pwszDataSourceType ={Marshal.PtrToStringUni(pwszDataSourceType)}");
             }
-            builder.Append("\tulParamSize  =" + ulParamSize.ToInt64().ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tdwFlags     =0x" + dwFlags.ToString("X4", CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tPrecision   =" + bPrecision.ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tScale       =" + bScale.ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
+            builder.AppendLine($"\tulParamSize  ={ulParamSize}");
+            builder.AppendLine($"\tdwFlags     =0x{dwFlags:X4}");
+            builder.AppendLine($"\tPrecision   ={bPrecision}");
+            builder.AppendLine($"\tScale       ={bScale}");
             return builder.ToString();
         }
 #endif
@@ -144,15 +144,15 @@ internal tagDBBINDING()
         public override string ToString()
         {
             StringBuilder builder = new StringBuilder();
-            builder.Append("tagDBBINDING").Append(Environment.NewLine);
-            builder.Append("\tOrdinal     =" + iOrdinal.ToInt64().ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tValueOffset =" + obValue.ToInt64().ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tLengthOffset=" + obLength.ToInt64().ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tStatusOffset=" + obStatus.ToInt64().ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tMaxLength   =" + cbMaxLen.ToInt64().ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tDB_Type     =" + ODB.WLookup(wType)).Append(Environment.NewLine);
-            builder.Append("\tPrecision   =" + bPrecision.ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\tScale       =" + bScale.ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
+            builder.AppendLine("tagDBBINDING");
+            builder.AppendLine($"\tOrdinal     ={iOrdinal}");
+            builder.AppendLine($"\tValueOffset ={obValue}");
+            builder.AppendLine($"\tLengthOffset={obLength}");
+            builder.AppendLine($"\tStatusOffset={obStatus}");
+            builder.AppendLine($"\tMaxLength   ={cbMaxLen}");
+            builder.AppendLine($"\tDB_Type     ={ODB.WLookup(wType)}");
+            builder.AppendLine($"\tPrecision   ={bPrecision}");
+            builder.AppendLine($"\tScale       ={bScale}");
             return builder.ToString();
         }
 #endif
@@ -442,14 +442,14 @@ internal tagDBCOLUMNINFO()
         public override string ToString()
         {
             StringBuilder builder = new StringBuilder();
-            builder.Append("tagDBCOLUMNINFO: " + Convert.ToString(pwszName, CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\t" + iOrdinal.ToInt64().ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\t" + "0x" + dwFlags.ToString("X8", CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\t" + ulColumnSize.ToInt64().ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\t" + "0x" + wType.ToString("X2", CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\t" + bPrecision.ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\t" + bScale.ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
-            builder.Append("\t" + columnid.eKind.ToString(CultureInfo.InvariantCulture)).Append(Environment.NewLine);
+            builder.AppendLine($"tagDBCOLUMNINFO: {Convert.ToString(pwszName, CultureInfo.InvariantCulture)}");
+            builder.AppendLine($"\t{iOrdinal.ToInt64().ToString(CultureInfo.InvariantCulture)}");
+            builder.AppendLine($"\t0x{dwFlags:X8}");
+            builder.AppendLine($"\t{ulColumnSize}");
+            builder.AppendLine($"\t0x{wType:X2}");
+            builder.AppendLine($"\t{bPrecision}");
+            builder.AppendLine($"\t{bScale}");
+            builder.AppendLine($"\t{columnid.eKind}");
             return builder.ToString();
         }
 #endif

diff --git a/src/libraries/System.Data.OleDb/src/OleDb_Util.cs b/src/libraries/System.Data.OleDb/src/OleDb_Util.cs
@@ -697,9 +697,7 @@ internal static string ELookup(OleDbHResult hr)
             {
                 builder.Length = 0;
             }
-            builder.Append("(0x");
-            builder.Append(((int)hr).ToString("X8", CultureInfo.InvariantCulture));
-            builder.Append(')');
+            builder.Append($"(0x{(int)hr:X8})");
             return builder.ToString();
         }
 
@@ -710,9 +708,7 @@ internal static string WLookup(short id)
             string? value = (string?)g_wlookpup[id];
             if (null == value)
             {
-                value = "0x" + ((short)id).ToString("X2", CultureInfo.InvariantCulture) + " " + ((short)id);
-                value += " " + ((DBTypeEnum)id).ToString();
-                g_wlookpup[id] = value;
+                g_wlookpup[id] = value = $"0x{(short)id:X2} {(short)id} {(DBTypeEnum)id}";
             }
             return value;
         }

diff --git a/src/libraries/System.Data.OleDb/src/System/Data/Common/AdapterUtil.cs b/src/libraries/System.Data.OleDb/src/System/Data/Common/AdapterUtil.cs
@@ -266,7 +266,7 @@ internal static ArgumentOutOfRangeException InvalidCommandType(CommandType value
                 case CommandType.Text:
                 case CommandType.StoredProcedure:
                 case CommandType.TableDirect:
-                    Debug.Assert(false, "valid CommandType " + value.ToString());
+                    Debug.Assert(false, $"valid CommandType {value}");
                     break;
             }
 #endif
@@ -283,7 +283,7 @@ internal static ArgumentOutOfRangeException InvalidDataRowVersion(DataRowVersion
                 case DataRowVersion.Current:
                 case DataRowVersion.Original:
                 case DataRowVersion.Proposed:
-                    Debug.Assert(false, "valid DataRowVersion " + value.ToString());
+                    Debug.Assert(false, $"valid DataRowVersion {value}");
                     break;
             }
 #endif
@@ -303,7 +303,7 @@ internal static ArgumentOutOfRangeException InvalidIsolationLevel(IsolationLevel
                 case IsolationLevel.RepeatableRead:
                 case IsolationLevel.Serializable:
                 case IsolationLevel.Snapshot:
-                    Debug.Assert(false, "valid IsolationLevel " + value.ToString());
+                    Debug.Assert(false, $"valid IsolationLevel {value}");
                     break;
             }
 #endif
@@ -320,7 +320,7 @@ internal static ArgumentOutOfRangeException InvalidParameterDirection(ParameterD
                 case ParameterDirection.Output:
                 case ParameterDirection.InputOutput:
                 case ParameterDirection.ReturnValue:
-                    Debug.Assert(false, "valid ParameterDirection " + value.ToString());
+                    Debug.Assert(false, $"valid ParameterDirection {value}");
                     break;
             }
 #endif
@@ -337,7 +337,7 @@ internal static ArgumentOutOfRangeException InvalidUpdateRowSource(UpdateRowSour
                 case UpdateRowSource.OutputParameters:
                 case UpdateRowSource.FirstReturnedRecord:
                 case UpdateRowSource.Both:
-                    Debug.Assert(false, "valid UpdateRowSource " + value.ToString());
+                    Debug.Assert(false, $"valid UpdateRowSource {value}");
                     break;
             }
 #endif

diff --git a/...ries/System.Diagnostics.FileVersionInfo/src/System/Diagnostics/FileVersionInfo.Windows.cs b/...ries/System.Diagnostics.FileVersionInfo/src/System/Diagnostics/FileVersionInfo.Windows.cs
@@ -65,7 +65,7 @@ private unsafe FileVersionInfo(string fileName)
 
         private static string ConvertTo8DigitHex(uint value)
         {
-            return value.ToString("X8", CultureInfo.InvariantCulture);
+            return value.ToString("X8");
         }
 
         private static Interop.Version.VS_FIXEDFILEINFO GetFixedFileInfo(IntPtr memPtr)
@@ -126,18 +126,20 @@ private static uint GetVarEntry(IntPtr memPtr)
         //
         private bool GetVersionInfoForCodePage(IntPtr memIntPtr, string codepage)
         {
-            _companyName = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\CompanyName");
-            _fileDescription = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\FileDescription");
-            _fileVersion = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\FileVersion");
-            _internalName = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\InternalName");
-            _legalCopyright = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\LegalCopyright");
-            _originalFilename = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\OriginalFilename");
-            _productName = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\ProductName");
-            _productVersion = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\ProductVersion");
-            _comments = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\Comments");
-            _legalTrademarks = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\LegalTrademarks");
-            _privateBuild = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\PrivateBuild");
-            _specialBuild = GetFileVersionString(memIntPtr, $"\\\\StringFileInfo\\\\{codepage}\\\\SpecialBuild");
+            Span<char> stackBuffer = stackalloc char[256];
+
+            _companyName = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\CompanyName"));
+            _fileDescription = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\FileDescription"));
+            _fileVersion = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\FileVersion"));
+            _internalName = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\InternalName"));
+            _legalCopyright = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\LegalCopyright"));
+            _originalFilename = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\OriginalFilename"));
+            _productName = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\ProductName"));
+            _productVersion = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\ProductVersion"));
+            _comments = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\Comments"));
+            _legalTrademarks = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\LegalTrademarks"));
+            _privateBuild = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\PrivateBuild"));
+            _specialBuild = GetFileVersionString(memIntPtr, string.Create(null, stackBuffer, $"\\\\StringFileInfo\\\\{codepage}\\\\SpecialBuild"));
 
             _language = GetFileVersionLanguage(memIntPtr);
 

diff --git a/...tem.Diagnostics.TextWriterTraceListener/src/System/Diagnostics/TextWriterTraceListener.cs b/...tem.Diagnostics.TextWriterTraceListener/src/System/Diagnostics/TextWriterTraceListener.cs
@@ -240,7 +240,7 @@ internal void EnsureWriter()
                     }
                     catch (IOException)
                     {
-                        fileNameOnly = Guid.NewGuid().ToString() + fileNameOnly;
+                        fileNameOnly = $"{Guid.NewGuid()}{fileNameOnly}";
                         fullPath = Path.Combine(dirPath, fileNameOnly);
                         continue;
                     }

diff --git a/src/libraries/System.Diagnostics.TraceSource/src/System/Diagnostics/TraceListener.cs b/src/libraries/System.Diagnostics.TraceSource/src/System/Diagnostics/TraceListener.cs
@@ -184,7 +184,7 @@ public virtual void Close()
 
         public virtual void TraceTransfer(TraceEventCache? eventCache, string source, int id, string? message, Guid relatedActivityId)
         {
-            TraceEvent(eventCache, source, TraceEventType.Transfer, id, message + ", relatedActivityId=" + relatedActivityId.ToString());
+            TraceEvent(eventCache, source, TraceEventType.Transfer, id, string.Create(null, stackalloc char[256], $"{message}, relatedActivityId={relatedActivityId}"));
         }
 
         /// <devdoc>
@@ -201,8 +201,8 @@ public virtual void Fail(string? message)
         public virtual void Fail(string? message, string? detailMessage)
         {
             WriteLine(detailMessage is null ?
-                SR.TraceListenerFail + " " + message :
-                SR.TraceListenerFail + " " + message + " " + detailMessage);
+                $"{SR.TraceListenerFail} {message}" :
+                $"{SR.TraceListenerFail} {message} {detailMessage}");
         }
 
         /// <devdoc>
@@ -390,7 +390,7 @@ public virtual void TraceEvent(TraceEventCache? eventCache, string source, Trace
 
         private void WriteHeader(string source, TraceEventType eventType, int id)
         {
-            Write($"{source} {eventType.ToString()}: {id.ToString(CultureInfo.InvariantCulture)} : ");
+            Write(string.Create(CultureInfo.InvariantCulture, stackalloc char[256], $"{source} {eventType}: {id} : "));
         }
 
         private void WriteFooter(TraceEventCache? eventCache)
@@ -425,14 +425,16 @@ private void WriteFooter(TraceEventCache? eventCache)
                 WriteLine(string.Empty);
             }
 
+            Span<char> stackBuffer = stackalloc char[128];
+
             if (IsEnabled(TraceOptions.ThreadId))
                 WriteLine("ThreadId=" + eventCache.ThreadId);
 
             if (IsEnabled(TraceOptions.DateTime))
-                WriteLine("DateTime=" + eventCache.DateTime.ToString("o", CultureInfo.InvariantCulture));
+                WriteLine(string.Create(null, stackBuffer, $"DateTime={eventCache.DateTime:o}"));
 
             if (IsEnabled(TraceOptions.Timestamp))
-                WriteLine("Timestamp=" + eventCache.Timestamp);
+                WriteLine(string.Create(null, stackBuffer, $"Timestamp={eventCache.Timestamp}"));
 
             if (IsEnabled(TraceOptions.Callstack))
                 WriteLine("Callstack=" + eventCache.Callstack);

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Brush.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Brush.cs
@@ -47,7 +47,7 @@ protected virtual void Dispose(bool disposing)
 #endif
                     Gdip.GdipDeleteBrush(new HandleRef(this, _nativeBrush));
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex) when (!ClientUtils.IsSecurityOrCriticalException(ex))

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Drawing2D/GraphicsPath.Windows.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Drawing2D/GraphicsPath.Windows.cs
@@ -94,7 +94,7 @@ private void Dispose(bool disposing)
 #endif
                     Gdip.GdipDeletePath(new HandleRef(this, _nativePath));
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex)

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Drawing2D/GraphicsPathIterator.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Drawing2D/GraphicsPathIterator.cs
@@ -38,7 +38,7 @@ private void Dispose(bool disposing)
 #endif
                     Gdip.GdipDeletePathIter(new HandleRef(this, nativeIter));
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex)

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Drawing2D/SafeCustomLineCapHandle.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Drawing2D/SafeCustomLineCapHandle.cs
@@ -48,7 +48,7 @@ protected override bool ReleaseHandle()
                 {
                     handle = IntPtr.Zero;
                 }
-                Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
             }
             return status == Gdip.Ok;
         }

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Font.Unix.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Font.Unix.cs
@@ -65,7 +65,7 @@ private void CreateFont(string familyName, float emSize, FontStyle style, Graphi
             int status = Gdip.GdipCreateFont(new HandleRef(this, family.NativeFamily), emSize, style, unit, out _nativeFont);
 
             if (status == Gdip.FontStyleNotFound)
-                throw new ArgumentException($"Style {style.ToString()} isn't supported by font {familyName}.");
+                throw new ArgumentException($"Style {style} isn't supported by font {familyName}.");
 
             Gdip.CheckStatus(status);
         }

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Font.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Font.cs
@@ -183,7 +183,7 @@ private void Dispose(bool disposing)
 #endif
                     Gdip.GdipDeleteFont(new HandleRef(this, _nativeFont));
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex) when (!ClientUtils.IsCriticalException(ex))

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/FontConverter.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/FontConverter.cs
@@ -40,7 +40,8 @@ public override bool CanConvertTo(ITypeDescriptorContext? context, Type? destina
 
                     ValueStringBuilder sb = default;
                     sb.Append(font.Name);
-                    sb.Append(culture.TextInfo.ListSeparator[0] + " ");
+                    sb.Append(culture.TextInfo.ListSeparator[0]);
+                    sb.Append(" ");
                     sb.Append(font.Size.ToString(culture.NumberFormat));
 
                     switch (font.Unit)
@@ -79,7 +80,8 @@ public override bool CanConvertTo(ITypeDescriptorContext? context, Type? destina
 
                     if (font.Style != FontStyle.Regular)
                     {
-                        sb.Append(culture.TextInfo.ListSeparator[0] + " style=");
+                        sb.Append(culture.TextInfo.ListSeparator[0]);
+                        sb.Append(" style=");
                         sb.Append(font.Style.ToString());
                     }
 

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/FontFamily.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/FontFamily.cs
@@ -162,7 +162,7 @@ private void Dispose(bool disposing)
 #endif
                     Gdip.GdipDeleteFontFamily(new HandleRef(this, _nativeFamily));
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex) when (!ClientUtils.IsCriticalException(ex))

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Graphics.Windows.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Graphics.Windows.cs
@@ -178,7 +178,7 @@ private void Dispose(bool disposing)
                     Gdip.GdipDeleteGraphics(new HandleRef(this, NativeGraphics));
 
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex) when (!ClientUtils.IsSecurityOrCriticalException(ex))

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Image.Windows.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Image.Windows.cs
@@ -95,7 +95,7 @@ protected virtual void Dispose(bool disposing)
 #endif
                 Gdip.GdipDisposeImage(new HandleRef(this, nativeImage));
 #if DEBUG
-                Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
             }
             catch (Exception ex)

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/FrameDimension.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/FrameDimension.cs
@@ -78,7 +78,7 @@ public override string ToString()
             if (this == s_time) return "Time";
             if (this == s_resolution) return "Resolution";
             if (this == s_page) return "Page";
-            return "[FrameDimension: " + _guid + "]";
+            return $"[FrameDimension: {_guid}]";
         }
     }
 }
diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/ImageAttributes.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/ImageAttributes.cs
@@ -94,7 +94,7 @@ private void Dispose(bool disposing)
 #endif
                     Gdip.GdipDisposeImageAttributes(new HandleRef(this, nativeImageAttributes));
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex)

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/ImageFormat.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/ImageFormat.cs
@@ -170,7 +170,7 @@ public override string ToString()
             if (this.Guid == s_tiff.Guid) return "Tiff";
             if (this.Guid == s_exif.Guid) return "Exif";
             if (this.Guid == s_icon.Guid) return "Icon";
-            return "[ImageFormat: " + _guid + "]";
+            return $"[ImageFormat: {_guid}]";
         }
     }
 }
diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Internal/SystemColorTracker.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Internal/SystemColorTracker.cs
@@ -55,7 +55,7 @@ internal static void Add(ISystemColorTracker obj)
                     list[index] = new WeakReference(obj);
                 else
                 {
-                    Debug.Assert(list[index].Target == null, "Trying to reuse a weak reference that isn't broken yet: list[" + index + "], length =" + list.Length);
+                    Debug.Assert(list[index].Target == null, $"Trying to reuse a weak reference that isn't broken yet: list[{index}], length = {list.Length}");
                     list[index].Target = obj;
                 }
             }

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Pen.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Pen.cs
@@ -161,7 +161,7 @@ private void Dispose(bool disposing)
 #endif
                     Gdip.GdipDeletePen(new HandleRef(this, NativePen));
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex) when (!ClientUtils.IsSecurityOrCriticalException(ex))

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/Margins.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/Margins.cs
@@ -235,14 +235,6 @@ public override bool Equals([NotNullWhen(true)] object? obj)
         /// <summary>
         /// Provides some interesting information for the Margins in String form.
         /// </summary>
-        public override string ToString()
-        {
-            return "[Margins"
-                + " Left=" + Left.ToString(CultureInfo.InvariantCulture)
-                + " Right=" + Right.ToString(CultureInfo.InvariantCulture)
-                + " Top=" + Top.ToString(CultureInfo.InvariantCulture)
-                + " Bottom=" + Bottom.ToString(CultureInfo.InvariantCulture)
-                + "]";
-        }
+        public override string ToString() => $"[Margins Left={Left} Right={Right} Top={Top} Bottom={Bottom}]";
     }
 }
diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PageSettings.Unix.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PageSettings.Unix.cs
@@ -255,9 +255,7 @@ public void SetHdevmode(IntPtr hdevmode)
             throw new NotImplementedException();
         }
 
-        public override string ToString()
-        {
-            return $"[{nameof(PageSettings)}: {nameof(Color)}={color}, {nameof(Landscape)}={landscape}, {nameof(Margins)}={margins}, {nameof(PaperSize)}={paperSize}, {nameof(PaperSource)}={paperSource}, {nameof(PrinterResolution)}={printerResolution}]";
-        }
+        public override string ToString() =>
+            $"[{nameof(PageSettings)}: {nameof(Color)}={color}, {nameof(Landscape)}={landscape}, {nameof(Margins)}={margins}, {nameof(PaperSize)}={paperSize}, {nameof(PaperSource)}={paperSource}, {nameof(PrinterResolution)}={printerResolution}]";
     }
 }
diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PageSettings.Windows.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PageSettings.Windows.cs
@@ -536,16 +536,7 @@ public void SetHdevmode(IntPtr hdevmode)
         /// <summary>
         /// Provides some interesting information about the PageSettings in String form.
         /// </summary>
-        public override string ToString()
-        {
-            return "[PageSettings:"
-            + " Color=" + Color.ToString()
-            + ", Landscape=" + Landscape.ToString()
-            + ", Margins=" + Margins.ToString()
-            + ", PaperSize=" + PaperSize.ToString()
-            + ", PaperSource=" + PaperSource.ToString()
-            + ", PrinterResolution=" + PrinterResolution.ToString()
-            + "]";
-        }
+        public override string ToString() =>
+            $"[{nameof(PageSettings)}: Color={Color}, Landscape={Landscape}, Margins={Margins}, PaperSize={PaperSize}, PaperSource={PaperSource}, PrinterResolution={PrinterResolution}]";
     }
 }
diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PaperSize.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PaperSize.cs
@@ -127,13 +127,6 @@ public int Width
         /// <summary>
         /// Provides some interesting information about the PaperSize in String form.
         /// </summary>
-        public override string ToString()
-        {
-            return "[PaperSize " + PaperName
-                + " Kind=" + Kind.ToString()
-                + " Height=" + Height.ToString(CultureInfo.InvariantCulture)
-                + " Width=" + Width.ToString(CultureInfo.InvariantCulture)
-                + "]";
-        }
+        public override string ToString() => $"[PaperSize {PaperName} Kind={Kind.ToString()} Height={Height.ToString(CultureInfo.InvariantCulture)} Width={Width.ToString(CultureInfo.InvariantCulture)}]";
     }
 }
diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PaperSource.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PaperSource.cs
@@ -63,11 +63,6 @@ public string SourceName
         /// <summary>
         /// Provides some interesting information about the PaperSource in String form.
         /// </summary>
-        public override string ToString()
-        {
-            return "[PaperSource " + SourceName
-                + " Kind=" + Kind.ToString()
-                + "]";
-        }
+        public override string ToString() => $"[PaperSource {SourceName} Kind={Kind}]";
     }
 }
diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PrintDocument.Unix.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PrintDocument.Unix.cs
@@ -187,10 +187,7 @@ public void Print()
             PrintController.OnEndPrint(this, printArgs);
         }
 
-        public override string ToString()
-        {
-            return "[PrintDocument " + this.DocumentName + "]";
-        }
+        public override string ToString() => $"[PrintDocument {this.DocumentName}]";
 
         // events
         protected virtual void OnBeginPrint(PrintEventArgs e)

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PrintDocument.Windows.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PrintDocument.Windows.cs
@@ -248,9 +248,6 @@ public void Print()
         /// <summary>
         /// Provides some interesting information about the PrintDocument in String form.
         /// </summary>
-        public override string ToString()
-        {
-            return "[PrintDocument " + DocumentName + "]";
-        }
+        public override string ToString() => $"[PrintDocument {DocumentName}]";
     }
 }
diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PrinterSettings.Unix.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PrinterSettings.Unix.cs
@@ -365,13 +365,7 @@ public void SetHdevnames(IntPtr hdevnames)
             throw new NotImplementedException();
         }
 
-        public override string ToString()
-        {
-            return "Printer [PrinterSettings " + printer_name + " Copies=" + copies + " Collate=" + collate
-            + " Duplex=" + can_duplex + " FromPage=" + from_page + " LandscapeAngle=" + landscape_angle
-            + " MaximumCopies=" + maximum_copies + " OutputPort=" + " ToPage=" + to_page + "]";
-
-        }
+        public override string ToString() => $"Printer [PrinterSettings {printer_name} Copies={copies} Collate={collate} Duplex={can_duplex} FromPage={from_page} LandscapeAngle={landscape_angle} MaximumCopies={maximum_copies} OutputPort= ToPage={to_page}]";
 
         // Public subclasses
         #region Public Subclasses

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PrinterSettings.Windows.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PrinterSettings.Windows.cs
@@ -1258,16 +1258,16 @@ public override string ToString()
         {
             string printerName = PrinterName;
             return "[PrinterSettings "
-            + printerName
-            + " Copies=" + Copies.ToString(CultureInfo.InvariantCulture)
-            + " Collate=" + Collate.ToString(CultureInfo.InvariantCulture)
-            + " Duplex=" + Duplex.ToString()
-            + " FromPage=" + FromPage.ToString(CultureInfo.InvariantCulture)
-            + " LandscapeAngle=" + LandscapeAngle.ToString(CultureInfo.InvariantCulture)
-            + " MaximumCopies=" + MaximumCopies.ToString(CultureInfo.InvariantCulture)
-            + " OutputPort=" + OutputPort.ToString(CultureInfo.InvariantCulture)
-            + " ToPage=" + ToPage.ToString(CultureInfo.InvariantCulture)
-            + "]";
+                + printerName
+                + " Copies=" + Copies.ToString(CultureInfo.InvariantCulture)
+                + " Collate=" + Collate.ToString(CultureInfo.InvariantCulture)
+                + " Duplex=" + Duplex.ToString()
+                + " FromPage=" + FromPage.ToString(CultureInfo.InvariantCulture)
+                + " LandscapeAngle=" + LandscapeAngle.ToString(CultureInfo.InvariantCulture)
+                + " MaximumCopies=" + MaximumCopies.ToString(CultureInfo.InvariantCulture)
+                + " OutputPort=" + OutputPort.ToString(CultureInfo.InvariantCulture)
+                + " ToPage=" + ToPage.ToString(CultureInfo.InvariantCulture)
+                + "]";
         }
 
         // Write null terminated string, return length of string in characters (including null)

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Region.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Region.cs
@@ -101,7 +101,7 @@ private void Dispose(bool disposing)
 #endif
                     Gdip.GdipDeleteRegion(new HandleRef(this, NativeRegion));
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex) when (!ClientUtils.IsSecurityOrCriticalException(ex))

diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/StringFormat.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/StringFormat.cs
@@ -86,7 +86,7 @@ private void Dispose(bool disposing)
 #endif
                     Gdip.GdipDeleteStringFormat(new HandleRef(this, nativeFormat));
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex)
@@ -442,9 +442,6 @@ internal int GetMeasurableCharacterRangeCount()
         /// <summary>
         /// Converts this <see cref='StringFormat'/> to a human-readable string.
         /// </summary>
-        public override string ToString()
-        {
-            return "[StringFormat, FormatFlags=" + FormatFlags.ToString() + "]";
-        }
+        public override string ToString() => $"[StringFormat, FormatFlags={FormatFlags.ToString()}]";
     }
 }
diff --git a/src/libraries/System.Drawing.Common/src/System/Drawing/Text/PrivateFontCollection.cs b/src/libraries/System.Drawing.Common/src/System/Drawing/Text/PrivateFontCollection.cs
@@ -37,7 +37,7 @@ protected override void Dispose(bool disposing)
 #endif
                     Gdip.GdipDeletePrivateFontCollection(ref _nativeFontCollection);
 #if DEBUG
-                    Debug.Assert(status == Gdip.Ok, "GDI+ returned an error status: " + status.ToString(CultureInfo.InvariantCulture));
+                    Debug.Assert(status == Gdip.Ok, $"GDI+ returned an error status: {status.ToString(CultureInfo.InvariantCulture)}");
 #endif
                 }
                 catch (Exception ex) when (!ClientUtils.IsSecurityOrCriticalException(ex))

diff --git a/src/libraries/System.Drawing.Primitives/src/System/Drawing/Color.cs b/src/libraries/System.Drawing.Primitives/src/System/Drawing/Color.cs
@@ -565,21 +565,10 @@ public float GetSaturation()
 
         public KnownColor ToKnownColor() => (KnownColor)knownColor;
 
-        public override string ToString()
-        {
-            if (IsNamedColor)
-            {
-                return nameof(Color) + " [" + Name + "]";
-            }
-            else if ((state & StateValueMask) != 0)
-            {
-                return nameof(Color) + " [A=" + A.ToString() + ", R=" + R.ToString() + ", G=" + G.ToString() + ", B=" + B.ToString() + "]";
-            }
-            else
-            {
-                return nameof(Color) + " [Empty]";
-            }
-        }
+        public override string ToString() =>
+            IsNamedColor ? $"{nameof(Color)} [{Name}]":
+            (state & StateValueMask) != 0 ? $"{nameof(Color)} [A={A}, R={R}, G={G}, B={B}]" :
+            $"{nameof(Color)} [Empty]";
 
         public static bool operator ==(Color left, Color right) =>
             left.value == right.value

diff --git a/src/libraries/System.Drawing.Primitives/src/System/Drawing/Point.cs b/src/libraries/System.Drawing.Primitives/src/System/Drawing/Point.cs
@@ -165,7 +165,7 @@ public void Offset(int dx, int dy)
         /// <summary>
         /// Converts this <see cref='System.Drawing.Point'/> to a human readable string.
         /// </summary>
-        public override readonly string ToString() => "{X=" + X.ToString() + ",Y=" + Y.ToString() + "}";
+        public override readonly string ToString() => $"{{X={X},Y={Y}}}";
 
         private static short HighInt16(int n) => unchecked((short)((n >> 16) & 0xffff));
 

diff --git a/src/libraries/System.Drawing.Primitives/src/System/Drawing/PointF.cs b/src/libraries/System.Drawing.Primitives/src/System/Drawing/PointF.cs
@@ -140,6 +140,6 @@ public float Y
 
         public override readonly int GetHashCode() => HashCode.Combine(X.GetHashCode(), Y.GetHashCode());
 
-        public override readonly string ToString() => "{X=" + x.ToString() + ", Y=" + y.ToString() + "}";
+        public override readonly string ToString() => $"{{X={x}, Y={y}}}";
     }
 }
diff --git a/src/libraries/System.Drawing.Primitives/src/System/Drawing/Rectangle.cs b/src/libraries/System.Drawing.Primitives/src/System/Drawing/Rectangle.cs
@@ -340,8 +340,6 @@ public void Offset(int x, int y)
         /// <summary>
         /// Converts the attributes of this <see cref='System.Drawing.Rectangle'/> to a human readable string.
         /// </summary>
-        public override readonly string ToString() =>
-            "{X=" + X.ToString() + ",Y=" + Y.ToString() +
-            ",Width=" + Width.ToString() + ",Height=" + Height.ToString() + "}";
+        public override readonly string ToString() => $"{{X={X},Y={Y},Width={Width},Height={Height}}}";
     }
 }
diff --git a/src/libraries/System.Drawing.Primitives/src/System/Drawing/RectangleF.cs b/src/libraries/System.Drawing.Primitives/src/System/Drawing/RectangleF.cs
@@ -326,8 +326,6 @@ public void Offset(float x, float y)
         /// Converts the <see cref='System.Drawing.RectangleF.Location'/> and <see cref='System.Drawing.RectangleF.Size'/>
         /// of this <see cref='System.Drawing.RectangleF'/> to a human-readable string.
         /// </summary>
-        public override readonly string ToString() =>
-            "{X=" + X.ToString() + ",Y=" + Y.ToString() +
-            ",Width=" + Width.ToString() + ",Height=" + Height.ToString() + "}";
+        public override readonly string ToString() => $"{{X={X},Y={Y},Width={Width},Height={Height}}}";
     }
 }
diff --git a/src/libraries/System.Drawing.Primitives/src/System/Drawing/Size.cs b/src/libraries/System.Drawing.Primitives/src/System/Drawing/Size.cs
@@ -189,7 +189,7 @@ public int Height
         /// <summary>
         /// Creates a human-readable string that represents this <see cref='System.Drawing.Size'/>.
         /// </summary>
-        public override readonly string ToString() => "{Width=" + width.ToString() + ", Height=" + height.ToString() + "}";
+        public override readonly string ToString() => $"{{Width={width}, Height={height}}}";
 
         /// <summary>
         /// Multiplies <see cref="Size"/> by an <see cref="int"/> producing <see cref="Size"/>.

diff --git a/src/libraries/System.Drawing.Primitives/src/System/Drawing/SizeF.cs b/src/libraries/System.Drawing.Primitives/src/System/Drawing/SizeF.cs
@@ -177,7 +177,7 @@ public float Height
         /// <summary>
         /// Creates a human-readable string that represents this <see cref='System.Drawing.SizeF'/>.
         /// </summary>
-        public override readonly string ToString() => "{Width=" + width.ToString() + ", Height=" + height.ToString() + "}";
+        public override readonly string ToString() => $"{{Width={width}, Height={height}}}";
 
         /// <summary>
         /// Multiplies <see cref="SizeF"/> by a <see cref="float"/> producing <see cref="SizeF"/>.

diff --git a/src/libraries/System.Formats.Asn1/tests/Writer/WriteInteger.cs b/src/libraries/System.Formats.Asn1/tests/Writer/WriteInteger.cs
@@ -278,7 +278,7 @@ public void VerifyWriteInteger_Context9_ULong(AsnEncodingRules ruleSet, ulong va
         [InlineData("FEFDFCFBFAF9F8F7F6F5F4F3F2F1F100")]
         public void VerifyWriteInteger_EncodedBytes(string valueHex)
         {
-            string expectedHex = "02" + (valueHex.Length / 2).ToString("X2") + valueHex;
+            string expectedHex = $"02{valueHex.Length / 2:X2}{valueHex}";
 
             AsnWriter writer = new AsnWriter(AsnEncodingRules.BER);
             writer.WriteInteger(valueHex.HexToByteArray());
@@ -298,7 +298,7 @@ public void VerifyWriteInteger_EncodedBytes(string valueHex)
         [InlineData("FEFDFCFBFAF9F8F7F6F5F4F3F2F1F100")]
         public void VerifyWriteInteger_Context4_EncodedBytes(string valueHex)
         {
-            string expectedHex = "84" + (valueHex.Length / 2).ToString("X2") + valueHex;
+            string expectedHex = $"84{valueHex.Length / 2:X2}{valueHex}";
 
             AsnWriter writer = new AsnWriter(AsnEncodingRules.BER);
             writer.WriteInteger(valueHex.HexToByteArray(), new Asn1Tag(TagClass.ContextSpecific, 4));

diff --git a/src/libraries/System.Globalization.Extensions/tests/Normalization/NormalizationAll.cs b/src/libraries/System.Globalization.Extensions/tests/Normalization/NormalizationAll.cs
@@ -167,8 +167,7 @@ private static string DumpStringAsCodepoints(string s)
             StringBuilder sb = new StringBuilder();
             for (int i=0; i<s.Length; i++)
             {
-                sb.Append("\\x");
-                sb.Append(((int)s[i]).ToString("X4"));
+                sb.Append($"\\x{(int)s[i]:X4}");
             }
             return sb.ToString();
         }

diff --git a/src/libraries/System.Globalization/tests/System/Globalization/CharUnicodeInfoTests.cs b/src/libraries/System.Globalization/tests/System/Globalization/CharUnicodeInfoTests.cs
@@ -122,7 +122,7 @@ public void GetNumericValue_Invalid()
 
         private static string ErrorMessage(char ch, object expected, object actual)
         {
-            return $"CodeValue: {((int)ch).ToString("X")}; Expected: {expected}; Actual: {actual}";
+            return $"CodeValue: {(int)ch:X}; Expected: {expected}; Actual: {actual}";
         }
 
         public static string s_numericsCodepoints =

diff --git a/src/libraries/System.IO.FileSystem/tests/PortedCommon/CommonUtilities.cs b/src/libraries/System.IO.FileSystem/tests/PortedCommon/CommonUtilities.cs
@@ -288,7 +288,7 @@ private void CreateFileSystem()
                 for (int k = 0; k < numOfDirPerDir; k++)
                 {
                     string dirName = GetNonExistingDir(dir, DirPrefixName);
-                    Debug.Assert(!Directory.Exists(dirName), string.Format("ERR_93472g! Directory exists: {0}", dirName));
+                    Debug.Assert(!Directory.Exists(dirName), $"ERR_93472g! Directory exists: {dirName}");
                     tempDirsForOneLevel.Add(dirName, new List<string>());
                     _listOfAllDirs.Add(dirName);
                     Directory.CreateDirectory(dirName);

diff --git a/src/libraries/System.IO.Hashing/tests/NonCryptoHashTestDriver.cs b/src/libraries/System.IO.Hashing/tests/NonCryptoHashTestDriver.cs
@@ -331,7 +331,7 @@ internal static string ToHexString(ReadOnlySpan<byte> input)
 
                 foreach (byte b in input)
                 {
-                    builder.Append(b.ToString("X2"));
+                    builder.Append($"{b:X2}");
                 }
 
                 return builder.ToString();

diff --git a/src/libraries/System.IO.IsolatedStorage/src/System/IO/IsolatedStorage/IsolatedStorage.cs b/src/libraries/System.IO.IsolatedStorage/src/System/IO/IsolatedStorage/IsolatedStorage.cs
@@ -153,7 +153,7 @@ protected void InitStore(IsolatedStorageScope scope, Type? domainEvidenceType, T
                 if (Helper.IsDomain(scope))
                 {
                     _domainIdentity = identity;
-                    hash = $"{hash}{SeparatorExternal}{hash}";
+                    hash = string.Create(null, stackalloc char[128], $"{hash}{SeparatorExternal}{hash}");
                 }
 
                 _assemblyIdentity = identity;

diff --git a/...ries/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Unix.cs b/...ries/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Unix.cs
@@ -174,7 +174,7 @@ private static FileStream CreateSharedBackingObject(Interop.Sys.MemoryMappedProt
            Interop.Sys.MemoryMappedProtections protections, long capacity, HandleInheritability inheritability)
         {
             // The POSIX shared memory object name must begin with '/'.  After that we just want something short and unique.
-            string mapName = "/corefx_map_" + Guid.NewGuid().ToString("N");
+            string mapName = string.Create(null, stackalloc char[128], $"/corefx_map_{Guid.NewGuid():N}");
 
             // Determine the flags to use when creating the shared memory object
             Interop.Sys.OpenFlags flags = (protections & Interop.Sys.MemoryMappedProtections.PROT_WRITE) != 0 ?

diff --git a/src/libraries/System.IO.Pipelines/tests/Infrastructure/TestMemoryPool.cs b/src/libraries/System.IO.Pipelines/tests/Infrastructure/TestMemoryPool.cs
@@ -59,7 +59,7 @@ public PooledMemory(IMemoryOwner<byte> owner, TestMemoryPool pool)
 
             ~PooledMemory()
             {
-                Debug.Assert(_returned, "Block being garbage collected instead of returned to pool" + Environment.NewLine + _leaser);
+                Debug.Assert(_returned, $"Block being garbage collected instead of returned to pool{Environment.NewLine}{_leaser}");
             }
 
             protected override void Dispose(bool disposing)

diff --git a/src/libraries/System.IO.Pipes/src/System/IO/Pipes/PipeCompletionSource.cs b/src/libraries/System.IO.Pipes/src/System/IO/Pipes/PipeCompletionSource.cs
@@ -156,7 +156,7 @@ private void Cancel()
 
         private void CompleteCallback(int resultState)
         {
-            Debug.Assert(resultState == ResultSuccess || resultState == ResultError, "Unexpected result state " + resultState);
+            Debug.Assert(resultState == ResultSuccess || resultState == ResultError, $"Unexpected result state {resultState}");
             CancellationToken cancellationToken = _cancellationRegistration.Token;
 
             ReleaseResources();

diff --git a/src/libraries/System.IO.Ports/src/System/IO/Ports/SerialStream.Windows.cs b/src/libraries/System.IO.Ports/src/System/IO/Ports/SerialStream.Windows.cs
@@ -1005,7 +1005,7 @@ internal unsafe int Read(byte[] array, int offset, int count, int timeout)
 
             if (count == 0) return 0; // return immediately if no bytes requested; no need for overhead.
 
-            Debug.Assert(timeout == SerialPort.InfiniteTimeout || timeout >= 0, "Serial Stream Read - called with timeout " + timeout);
+            Debug.Assert(timeout == SerialPort.InfiniteTimeout || timeout >= 0, $"Serial Stream Read - called with timeout {timeout}");
 
             int numBytes = 0;
             if (_isAsync)
@@ -1069,7 +1069,7 @@ internal unsafe void Write(byte[] array, int offset, int count, int timeout)
 
             if (count == 0) return; // no need to expend overhead in creating asyncResult, etc.
 
-            Debug.Assert(timeout == SerialPort.InfiniteTimeout || timeout >= 0, "Serial Stream Write - write timeout is " + timeout);
+            Debug.Assert(timeout == SerialPort.InfiniteTimeout || timeout >= 0, $"Serial Stream Write - write timeout is {timeout}");
 
             int numBytes;
             if (_isAsync)
@@ -1627,7 +1627,7 @@ internal unsafe void WaitForCommEvent()
                                 // if we get IO pending, MSDN says we should wait on the WaitHandle, then call GetOverlappedResult
                                 // to get the results of WaitCommEvent.
                                 bool success = waitCommEventWaitHandle.WaitOne();
-                                Debug.Assert(success, "waitCommEventWaitHandle.WaitOne() returned error " + Marshal.GetLastWin32Error());
+                                Debug.Assert(success, $"waitCommEventWaitHandle.WaitOne() returned error {Marshal.GetLastWin32Error()}");
 
                                 do
                                 {

diff --git a/src/libraries/System.IO.Ports/tests/SerialPort/GetPortNames.cs b/src/libraries/System.IO.Ports/tests/SerialPort/GetPortNames.cs
@@ -80,8 +80,8 @@ static string PortInformationString
             get
             {
                 var sb = new StringBuilder();
-                sb.AppendLine("PortHelper Ports: " + string.Join(",", PortHelper.GetPorts()));
-                sb.AppendLine("SerialPort Ports: " + string.Join(",", SerialPort.GetPortNames()));
+                sb.AppendLine($"PortHelper Ports: {string.Join(",", PortHelper.GetPorts())}");
+                sb.AppendLine($"SerialPort Ports: {string.Join(",", SerialPort.GetPortNames())}");
                 return sb.ToString();
             }
         }

diff --git a/src/libraries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/BranchLabel.cs b/src/libraries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/BranchLabel.cs
@@ -20,10 +20,8 @@ public RuntimeLabel(int index, int continuationStackDepth, int stackDepth)
             StackDepth = stackDepth;
         }
 
-        public override string ToString()
-        {
-            return string.Format(CultureInfo.InvariantCulture, "->{0} C({1}) S({2})", Index, ContinuationStackDepth, StackDepth);
-        }
+        public override string ToString() =>
+            string.Create(CultureInfo.InvariantCulture, $"->{Index} C({ContinuationStackDepth}) S({StackDepth})");
     }
 
     internal sealed class BranchLabel

diff --git a/...raries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/InstructionList.cs b/...raries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/InstructionList.cs
@@ -195,15 +195,15 @@ private void UpdateStackDepth(Instruction instruction)
                 instruction.ConsumedContinuations >= 0 && instruction.ProducedContinuations >= 0, "bad instruction " + instruction.ToString());
 
             _currentStackDepth -= instruction.ConsumedStack;
-            Debug.Assert(_currentStackDepth >= 0, "negative stack depth " + instruction.ToString());
+            Debug.Assert(_currentStackDepth >= 0, $"negative stack depth {instruction}");
             _currentStackDepth += instruction.ProducedStack;
             if (_currentStackDepth > _maxStackDepth)
             {
                 _maxStackDepth = _currentStackDepth;
             }
 
             _currentContinuationsDepth -= instruction.ConsumedContinuations;
-            Debug.Assert(_currentContinuationsDepth >= 0, "negative continuations " + instruction.ToString());
+            Debug.Assert(_currentContinuationsDepth >= 0, $"negative continuations {instruction}");
             _currentContinuationsDepth += instruction.ProducedContinuations;
             if (_currentContinuationsDepth > _maxContinuationDepth)
             {

diff --git a/...ibraries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/LightCompiler.cs b/...ibraries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/LightCompiler.cs
@@ -51,7 +51,7 @@ internal ExceptionHandler(int labelIndex, int handlerStartIndex, int handlerEndI
         public bool Matches(Type exceptionType) => _exceptionType.IsAssignableFrom(exceptionType);
 
         public override string ToString() =>
-            string.Format(CultureInfo.InvariantCulture, "catch ({0}) [{1}->{2}]", _exceptionType.Name, HandlerStartIndex, HandlerEndIndex);
+            string.Create(CultureInfo.InvariantCulture, $"catch ({_exceptionType.Name}) [{HandlerStartIndex}->{HandlerEndIndex}]");
     }
 
     internal sealed class TryCatchFinallyHandler
@@ -251,11 +251,11 @@ public override string ToString()
         {
             if (IsClear)
             {
-                return string.Format(CultureInfo.InvariantCulture, "{0}: clear", Index);
+                return string.Create(CultureInfo.InvariantCulture, $"{Index}: clear");
             }
             else
             {
-                return string.Format(CultureInfo.InvariantCulture, "{0}: [{1}-{2}] '{3}'", Index, StartLine, EndLine, FileName);
+                return string.Create(CultureInfo.InvariantCulture, $"{Index}: [{StartLine}-{EndLine}] '{FileName}'");
             }
         }
     }

diff --git a/src/libraries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/LightLambda.cs b/src/libraries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/LightLambda.cs
@@ -167,7 +167,7 @@ public override string ToString()
 
                     InstructionList.DebugView.InstructionView instructionView = instructionViews[i];
 
-                    sb.AppendFormat(CultureInfo.InvariantCulture, "{0}IP_{1}: {2}", _indent, i.ToString().PadLeft(4, '0'), instructionView.GetValue()).AppendLine();
+                    sb.AppendLine(CultureInfo.InvariantCulture, $"{_indent}IP_{i.ToString().PadLeft(4, '0')}: {instructionView.GetValue()}");
                 }
 
                 EmitExits(sb, instructions.Length);

diff --git a/...braries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/LocalVariables.cs b/...braries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/LocalVariables.cs
@@ -40,10 +40,8 @@ internal LocalVariable(int index, bool closure)
             _flags = (closure ? InClosureFlag : 0);
         }
 
-        public override string ToString()
-        {
-            return string.Format(CultureInfo.InvariantCulture, "{0}: {1} {2}", Index, IsBoxed ? "boxed" : null, InClosure ? "in closure" : null);
-        }
+        public override string ToString() =>
+            string.Create(CultureInfo.InvariantCulture, $"{Index}: {(IsBoxed ? "boxed" : null)} {(InClosure ? "in closure" : null)}");
     }
 
     internal readonly struct LocalDefinition

diff --git a/...raries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/StackOperations.cs b/...raries/System.Linq.Expressions/src/System/Linq/Expressions/Interpreter/StackOperations.cs
@@ -45,10 +45,8 @@ public override int Run(InterpretedFrame frame)
             return 1;
         }
 
-        public override string ToDebugString(int instructionIndex, object? cookie, Func<int, int> labelIndexer, IReadOnlyList<object>? objects)
-        {
-            return string.Format(CultureInfo.InvariantCulture, "LoadCached({0}: {1})", _index, objects![(int)_index]);
-        }
+        public override string ToDebugString(int instructionIndex, object? cookie, Func<int, int> labelIndexer, IReadOnlyList<object>? objects) =>
+            string.Create(CultureInfo.InvariantCulture, $"LoadCached({_index}: {objects![(int)_index]})");
 
         public override string ToString() => "LoadCached(" + _index + ")";
     }

diff --git a/src/libraries/System.Net.Http.WinHttpHandler/src/System/Net/Http/WinHttpRequestState.cs b/src/libraries/System.Net.Http.WinHttpHandler/src/System/Net/Http/WinHttpRequestState.cs
@@ -175,7 +175,7 @@ private void Dispose(bool disposing)
 #if DEBUG
             Interlocked.Increment(ref s_dbg_callDispose);
 #endif
-            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"GCHandle=0x{ToIntPtr().ToString("X")}, disposed={_disposed}, disposing={disposing}");
+            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"GCHandle=0x{ToIntPtr():X}, disposed={_disposed}, disposing={disposing}");
 
             // Since there is no finalizer and this class is sealed, the disposing parameter should be TRUE.
             Debug.Assert(disposing, "WinHttpRequestState.Dispose() should have disposing=TRUE");

diff --git a/src/libraries/System.Net.Http.WinHttpHandler/src/System/Net/Http/WinHttpTraceHelper.cs b/src/libraries/System.Net.Http.WinHttpHandler/src/System/Net/Http/WinHttpTraceHelper.cs
@@ -15,7 +15,7 @@ public static void TraceCallbackStatus(object thisOrContextObject, IntPtr handle
 
             NetEventSource.Info(
                 thisOrContextObject,
-                $"handle=0x{handle.ToString("X")}, context=0x{context.ToString("X")}, {GetStringFromInternetStatus(status)}",
+                $"handle=0x{handle:X}, context=0x{context:X}, {GetStringFromInternetStatus(status)}",
                 memberName);
         }
 

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/Headers/AltSvcHeaderValue.cs b/src/libraries/System.Net.Http/src/System/Net/Http/Headers/AltSvcHeaderValue.cs
@@ -56,13 +56,12 @@ public override string ToString()
             sb.Append("=\"");
             if (Host != null) sb.Append(Host);
             sb.Append(':');
-            sb.Append(Port.ToString(CultureInfo.InvariantCulture));
+            sb.Append((uint)Port);
             sb.Append('"');
 
             if (MaxAge != TimeSpan.FromTicks(AltSvcHeaderParser.DefaultMaxAgeTicks))
             {
-                sb.Append("; ma=");
-                sb.Append((MaxAge.Ticks / TimeSpan.TicksPerSecond).ToString(CultureInfo.InvariantCulture));
+                sb.Append(CultureInfo.InvariantCulture, $"; ma={MaxAge.Ticks / TimeSpan.TicksPerSecond}");
             }
 
             if (Persist)

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/Headers/CacheControlHeaderValue.cs b/src/libraries/System.Net.Http/src/System/Net/Http/Headers/CacheControlHeaderValue.cs
@@ -205,7 +205,7 @@ public override string ToString()
                 {
                     // In the corner case where the value is negative, ensure it uses
                     // the invariant's negative sign rather than the current culture's.
-                    sb.Append(maxAge.ToString(NumberFormatInfo.InvariantInfo));
+                    sb.Append(NumberFormatInfo.InvariantInfo, $"{maxAge}");
                 }
             }
 
@@ -222,7 +222,7 @@ public override string ToString()
                 {
                     // In the corner case where the value is negative, ensure it uses
                     // the invariant's negative sign rather than the current culture's.
-                    sb.Append(sharedMaxAge.ToString(NumberFormatInfo.InvariantInfo));
+                    sb.Append(NumberFormatInfo.InvariantInfo, $"{sharedMaxAge}");
                 }
             }
 
@@ -241,7 +241,7 @@ public override string ToString()
                     {
                         // In the corner case where the value is negative, ensure it uses
                         // the invariant's negative sign rather than the current culture's.
-                        sb.Append(maxStaleLimit.ToString(NumberFormatInfo.InvariantInfo));
+                        sb.Append(NumberFormatInfo.InvariantInfo, $"{maxStaleLimit}");
                     }
                 }
             }
@@ -259,7 +259,7 @@ public override string ToString()
                 {
                     // In the corner case where the value is negative, ensure it uses
                     // the invariant's negative sign rather than the current culture's.
-                    sb.Append(minFresh.ToString(NumberFormatInfo.InvariantInfo));
+                    sb.Append(NumberFormatInfo.InvariantInfo, $"{minFresh}");
                 }
             }
 

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/Headers/HttpHeaders.cs b/src/libraries/System.Net.Http/src/System/Net/Http/Headers/HttpHeaders.cs
@@ -449,7 +449,7 @@ internal bool RemoveParsedValue(HeaderDescriptor descriptor, object value)
                 if (info.IsEmpty)
                 {
                     bool headerRemoved = Remove(descriptor);
-                    Debug.Assert(headerRemoved, "Existing header '" + descriptor.Name + "' couldn't be removed.");
+                    Debug.Assert(headerRemoved, $"Existing header '{descriptor.Name}' couldn't be removed.");
                 }
 
                 return result;

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/Headers/RangeItemHeaderValue.cs b/src/libraries/System.Net.Http/src/System/Net/Http/Headers/RangeItemHeaderValue.cs
@@ -56,17 +56,20 @@ internal RangeItemHeaderValue(RangeItemHeaderValue source)
 
         public override string ToString()
         {
+            Span<char> stackBuffer = stackalloc char[128];
+
             if (!_from.HasValue)
             {
                 Debug.Assert(_to != null);
-                return "-" + _to.Value.ToString(NumberFormatInfo.InvariantInfo);
+                return string.Create(CultureInfo.InvariantCulture, stackBuffer, $"-{_to.Value}");
             }
-            else if (!_to.HasValue)
+
+            if (!_to.HasValue)
             {
-                return _from.Value.ToString(NumberFormatInfo.InvariantInfo) + "-";
+                return string.Create(CultureInfo.InvariantCulture, stackBuffer, $"{_from.Value}-"); ;
             }
-            return _from.Value.ToString(NumberFormatInfo.InvariantInfo) + "-" +
-                _to.Value.ToString(NumberFormatInfo.InvariantInfo);
+
+            return string.Create(CultureInfo.InvariantCulture, stackBuffer, $"{_from.Value}-{_to.Value}");
         }
 
         public override bool Equals([NotNullWhen(true)] object? obj)

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/Headers/StringWithQualityHeaderValue.cs b/src/libraries/System.Net.Http/src/System/Net/Http/Headers/StringWithQualityHeaderValue.cs
@@ -54,7 +54,7 @@ public override string ToString()
         {
             if (_quality.HasValue)
             {
-                return _value + "; q=" + _quality.Value.ToString("0.0##", NumberFormatInfo.InvariantInfo);
+                return string.Create(CultureInfo.InvariantCulture, stackalloc char[128], $"{_value}; q={_quality.Value:0.0##}");
             }
 
             return _value;

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/Headers/WarningHeaderValue.cs b/src/libraries/System.Net.Http/src/System/Net/Http/Headers/WarningHeaderValue.cs
@@ -74,7 +74,7 @@ public override string ToString()
             StringBuilder sb = StringBuilderCache.Acquire();
 
             // Warning codes are always 3 digits according to RFC2616
-            sb.Append(_code.ToString("000", NumberFormatInfo.InvariantInfo));
+            sb.Append(NumberFormatInfo.InvariantInfo, $"{_code:000}");
 
             sb.Append(' ');
             sb.Append(_agent);

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/HttpContent.cs b/src/libraries/System.Net.Http/src/System/Net/Http/HttpContent.cs
@@ -80,35 +80,31 @@ private static void AssertEncodingConstants(Encoding encoding, int codePage, int
             Debug.Assert(preamble != null);
 
             Debug.Assert(codePage == encoding.CodePage,
-                "Encoding code page mismatch for encoding: " + encoding.EncodingName,
-                "Expected (constant): {0}, Actual (Encoding.CodePage): {1}", codePage, encoding.CodePage);
+                $"Encoding code page mismatch for encoding: {encoding.EncodingName}",
+                $"Expected (constant): {codePage}, Actual (Encoding.CodePage): {encoding.CodePage}");
 
             byte[] actualPreamble = encoding.GetPreamble();
 
             Debug.Assert(preambleLength == actualPreamble.Length,
-                "Encoding preamble length mismatch for encoding: " + encoding.EncodingName,
-                "Expected (constant): {0}, Actual (Encoding.GetPreamble().Length): {1}", preambleLength, actualPreamble.Length);
+                $"Encoding preamble length mismatch for encoding: {encoding.EncodingName}",
+                $"Expected (constant): {preambleLength}, Actual (Encoding.GetPreamble().Length): {actualPreamble.Length}");
 
             Debug.Assert(actualPreamble.Length >= 2);
             int actualFirst2Bytes = actualPreamble[0] << 8 | actualPreamble[1];
 
             Debug.Assert(first2Bytes == actualFirst2Bytes,
-                "Encoding preamble first 2 bytes mismatch for encoding: " + encoding.EncodingName,
-                "Expected (constant): {0}, Actual: {1}", first2Bytes, actualFirst2Bytes);
+                $"Encoding preamble first 2 bytes mismatch for encoding: {encoding.EncodingName}",
+                $"Expected (constant): {first2Bytes}, Actual: {actualFirst2Bytes}");
 
             Debug.Assert(preamble.Length == actualPreamble.Length,
-                "Encoding preamble mismatch for encoding: " + encoding.EncodingName,
-                "Expected (constant): {0}, Actual (Encoding.GetPreamble()): {1}",
-                BitConverter.ToString(preamble),
-                BitConverter.ToString(actualPreamble));
+                $"Encoding preamble mismatch for encoding: {encoding.EncodingName}",
+                $"Expected (constant): {BitConverter.ToString(preamble)}, Actual (Encoding.GetPreamble()): {BitConverter.ToString(actualPreamble)}");
 
             for (int i = 0; i < preamble.Length; i++)
             {
                 Debug.Assert(preamble[i] == actualPreamble[i],
-                    "Encoding preamble mismatch for encoding: " + encoding.EncodingName,
-                    "Expected (constant): {0}, Actual (Encoding.GetPreamble()): {1}",
-                    BitConverter.ToString(preamble),
-                    BitConverter.ToString(actualPreamble));
+                    $"Encoding preamble mismatch for encoding: {encoding.EncodingName}",
+                    $"Expected (constant): {BitConverter.ToString(preamble)}, Actual (Encoding.GetPreamble()): {BitConverter.ToString(actualPreamble)}");
             }
         }
 #endif

diff --git a/...ies/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/AuthenticationHelper.NtAuth.cs b/...ies/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/AuthenticationHelper.NtAuth.cs
@@ -108,7 +108,7 @@ private static async Task<HttpResponseMessage> SendWithNtAuthAsync(HttpRequestMe
 
                             if (!isProxyAuth && !authUri.IsDefaultPort)
                             {
-                                hostName = $"{hostName}:{authUri.Port}";
+                                hostName = string.Create(null, stackalloc char[128], $"{hostName}:{authUri.Port}");
                             }
                         }
 

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http3Connection.cs b/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http3Connection.cs
@@ -9,6 +9,7 @@
 using System.IO;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Globalization;
 using System.Net.Http.Headers;
 using System.Net.Security;
 
@@ -78,7 +79,7 @@ public Http3Connection(HttpConnectionPool pool, HttpAuthority? origin, HttpAutho
             _connection = connection;
 
             bool altUsedDefaultPort = pool.Kind == HttpConnectionKind.Http && authority.Port == HttpConnectionPool.DefaultHttpPort || pool.Kind == HttpConnectionKind.Https && authority.Port == HttpConnectionPool.DefaultHttpsPort;
-            string altUsedValue = altUsedDefaultPort ? authority.IdnHost : authority.IdnHost + ":" + authority.Port.ToString(Globalization.CultureInfo.InvariantCulture);
+            string altUsedValue = altUsedDefaultPort ? authority.IdnHost : string.Create(CultureInfo.InvariantCulture, $"{authority.IdnHost}:{authority.Port}");
             _altUsedEncodedHeader = QPack.QPackEncoder.EncodeLiteralHeaderFieldWithoutNameReferenceToArray(KnownHeaders.AltUsed.Name, altUsedValue);
 
             // Errors are observed via Abort().

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs b/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs
@@ -349,15 +349,12 @@ public byte[] Http2AltSvcOriginUri
                     var sb = new StringBuilder();
 
                     Debug.Assert(_originAuthority != null);
-                    sb
-                        .Append(IsSecure ? "https://" : "http://")
-                        .Append(_originAuthority.IdnHost);
+                    sb.Append(IsSecure ? "https://" : "http://")
+                      .Append(_originAuthority.IdnHost);
 
                     if (_originAuthority.Port != (IsSecure ? DefaultHttpsPort : DefaultHttpPort))
                     {
-                        sb
-                            .Append(':')
-                            .Append(_originAuthority.Port.ToString(CultureInfo.InvariantCulture));
+                        sb.Append(CultureInfo.InvariantCulture, $":{_originAuthority.Port}");
                     }
 
                     _http2AltSvcOriginUri = Encoding.ASCII.GetBytes(sb.ToString());

diff --git a/src/libraries/System.Net.HttpListener/src/System/Net/HttpListenerException.cs b/src/libraries/System.Net.HttpListener/src/System/Net/HttpListenerException.cs
@@ -13,23 +13,23 @@ public class HttpListenerException : Win32Exception
     {
         public HttpListenerException() : base(Marshal.GetLastPInvokeError())
         {
-            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, NativeErrorCode.ToString() + ":" + Message);
+            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"{NativeErrorCode}:{Message}");
         }
 
         public HttpListenerException(int errorCode) : base(errorCode)
         {
-            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, NativeErrorCode.ToString() + ":" + Message);
+            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"{NativeErrorCode}:{Message}");
         }
 
         public HttpListenerException(int errorCode, string message) : base(errorCode, message)
         {
-            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, NativeErrorCode.ToString() + ":" + Message);
+            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"{NativeErrorCode}:{Message}");
         }
 
         protected HttpListenerException(SerializationInfo serializationInfo, StreamingContext streamingContext)
             : base(serializationInfo, streamingContext)
         {
-            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, NativeErrorCode.ToString() + ":" + Message);
+            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"{NativeErrorCode}:{Message}");
         }
 
         // the base class returns the HResult with this property

diff --git a/src/libraries/System.Net.HttpListener/src/System/Net/HttpListenerRequestUriBuilder.cs b/src/libraries/System.Net.HttpListener/src/System/Net/HttpListenerRequestUriBuilder.cs
@@ -119,8 +119,7 @@ private void BuildRequestUriUsingRawPath()
 
         private static Encoding GetEncoding(EncodingType type)
         {
-            Debug.Assert((type == EncodingType.Primary) || (type == EncodingType.Secondary),
-                "Unknown 'EncodingType' value: " + type.ToString());
+            Debug.Assert((type == EncodingType.Primary) || (type == EncodingType.Secondary), $"Unknown 'EncodingType' value: {type}");
 
             if (type == EncodingType.Secondary)
             {
@@ -330,8 +329,7 @@ private static void AppendOctetsPercentEncoded(StringBuilder target, IEnumerable
         {
             foreach (byte octet in octets)
             {
-                target.Append('%');
-                target.Append(octet.ToString("X2", CultureInfo.InvariantCulture));
+                target.Append($"%{octet:X2}");
             }
         }
 
@@ -350,7 +348,7 @@ private static string GetOctetsAsString(IEnumerable<byte> octets)
                 {
                     octetString.Append(' ');
                 }
-                octetString.Append(octet.ToString("X2", CultureInfo.InvariantCulture));
+                octetString.Append($"{octet:X2}");
             }
 
             return octetString.ToString();

diff --git a/src/libraries/System.Net.HttpListener/src/System/Net/Windows/HttpListener.Windows.cs b/src/libraries/System.Net.HttpListener/src/System/Net/Windows/HttpListener.Windows.cs
@@ -962,7 +962,7 @@ public HttpListenerContext EndGetContext(IAsyncResult asyncResult)
                                                 if (NetEventSource.Log.IsEnabled())
                                                 {
                                                     NetEventSource.Info(this,
-                                                        $"HandleAuthentication creating new WindowsIdentity from user context: {userContext.DangerousGetHandle().ToString("x8")}");
+                                                        $"HandleAuthentication creating new WindowsIdentity from user context: {userContext.DangerousGetHandle():x8}");
                                                 }
 
                                                 WindowsPrincipal windowsPrincipal = new WindowsPrincipal(
@@ -1881,7 +1881,7 @@ private static unsafe void IOCompleted(DisconnectAsyncResult asyncResult, uint e
 
             private static unsafe void WaitCallback(uint errorCode, uint numBytes, NativeOverlapped* nativeOverlapped)
             {
-                if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(null, $"errorCode: {errorCode}, numBytes: {numBytes}, nativeOverlapped: {((IntPtr)nativeOverlapped).ToString("x")}");
+                if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(null, $"errorCode: {errorCode}, numBytes: {numBytes}, nativeOverlapped: {(IntPtr)nativeOverlapped:x}");
                 // take the DisconnectAsyncResult object from the state
                 DisconnectAsyncResult asyncResult = (DisconnectAsyncResult)ThreadPoolBoundHandle.GetNativeOverlappedState(nativeOverlapped)!;
                 IOCompleted(asyncResult, errorCode, numBytes, nativeOverlapped);

diff --git a/src/libraries/System.Net.HttpListener/src/System/Net/Windows/HttpRequestStream.Windows.cs b/src/libraries/System.Net.HttpListener/src/System/Net/Windows/HttpRequestStream.Windows.cs
@@ -306,7 +306,7 @@ internal void IOCompleted(uint errorCode, uint numBytes)
 
             private static void IOCompleted(HttpRequestStreamAsyncResult asyncResult, uint errorCode, uint numBytes)
             {
-                if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(null, $"asyncResult: {asyncResult} errorCode:0x {errorCode.ToString("x8")} numBytes: {numBytes}");
+                if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(null, $"asyncResult: {asyncResult} errorCode:0x {errorCode:x8} numBytes: {numBytes}");
                 object? result = null;
                 try
                 {
@@ -333,7 +333,7 @@ private static unsafe void Callback(uint errorCode, uint numBytes, NativeOverlap
             {
                 HttpRequestStreamAsyncResult asyncResult = (HttpRequestStreamAsyncResult)ThreadPoolBoundHandle.GetNativeOverlappedState(nativeOverlapped)!;
 
-                if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(null, $"asyncResult: {asyncResult} errorCode:0x {errorCode.ToString("x8")} numBytes: {numBytes} nativeOverlapped:0x {((IntPtr)nativeOverlapped).ToString("x8")}");
+                if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(null, $"asyncResult: {asyncResult} errorCode:0x {errorCode:x8} numBytes: {numBytes} nativeOverlapped:0x{(IntPtr)nativeOverlapped:x8}");
 
                 IOCompleted(asyncResult, errorCode, numBytes);
             }

diff --git a/...libraries/System.Net.HttpListener/src/System/Net/Windows/HttpResponseStreamAsyncResult.cs b/...libraries/System.Net.HttpListener/src/System/Net/Windows/HttpResponseStreamAsyncResult.cs
@@ -185,7 +185,7 @@ internal void IOCompleted(uint errorCode, uint numBytes)
 
         private static void IOCompleted(HttpResponseStreamAsyncResult asyncResult, uint errorCode, uint numBytes)
         {
-            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(null, $"errorCode:0x {errorCode.ToString("x8")} numBytes: {numBytes}");
+            if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(null, $"errorCode:0x{errorCode:x8} numBytes: {numBytes}");
             object? result = null;
             try
             {

diff --git a/src/libraries/System.Net.HttpListener/src/System/Net/Windows/ListenerAsyncResult.Windows.cs b/src/libraries/System.Net.HttpListener/src/System/Net/Windows/ListenerAsyncResult.Windows.cs
@@ -106,7 +106,7 @@ internal uint QueueBeginGetContext()
             while (true)
             {
                 Debug.Assert(_requestContext != null);
-                if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"Calling Interop.HttpApi.HttpReceiveHttpRequest RequestId: {_requestContext.RequestBlob->RequestId}Buffer:0x {((IntPtr)_requestContext.RequestBlob).ToString("x")} Size: {_requestContext.Size}");
+                if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"Calling Interop.HttpApi.HttpReceiveHttpRequest RequestId: {_requestContext.RequestBlob->RequestId} Buffer: 0x{(IntPtr)_requestContext.RequestBlob:x} Size: {_requestContext.Size}");
                 uint bytesTransferred = 0;
                 Debug.Assert(AsyncObject != null);
                 HttpListenerSession listenerSession = (HttpListenerSession)AsyncObject!;

diff --git a/...raries/System.Net.HttpListener/src/System/Net/Windows/WebSockets/HttpWebSocket.Windows.cs b/...raries/System.Net.HttpListener/src/System/Net/Windows/WebSockets/HttpWebSocket.Windows.cs
@@ -137,15 +137,6 @@ internal static partial class HttpWebSocket
             return webSocketContext;
         }
 
-        internal static string GetTraceMsgForParameters(int offset, int count, CancellationToken cancellationToken)
-        {
-            return string.Format(CultureInfo.InvariantCulture,
-                "offset: {0}, count: {1}, cancellationToken.CanBeCanceled: {2}",
-                offset,
-                count,
-                cancellationToken.CanBeCanceled);
-        }
-
         internal static ConfiguredTaskAwaitable SuppressContextFlow(this Task task)
         {
             // We don't flow the synchronization context within WebSocket.xxxAsync - but the calling application
-Original file line number
+Diff line change
@@ Expand Up / @@ -608,7 +608,7 @@ private void MergeRelation(DataRelation relation) @@
                     }
                     else
                     {
-                        Debug.Assert(MissingSchemaAction.Error == _missingSchemaAction, "Unexpected value of MissingSchemaAction parameter : " + _missingSchemaAction.ToString());
+                        Debug.Assert(MissingSchemaAction.Error == _missingSchemaAction, $"Unexpected value of MissingSchemaAction parameter : {_missingSchemaAction}");
                         throw ExceptionBuilder.MergeMissingDefinition(relation.RelationName);
                     }
                 }
@@ Expand Down @@