Enable nullability and fix warnings

snippets/csharp/Microsoft.Extensions.DependencyModel/DependencyContext/Overview/DependencyContextSnippets.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

snippets/csharp/Microsoft.SqlServer.Server/SqlFunctionAttribute/Function.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Library</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

snippets/csharp/Microsoft.SqlServer.Server/SqlUserDefinedAggregateAttribute/Aggregate.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Library</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

snippets/csharp/Microsoft.SqlServer.Server/SqlUserDefinedTypeAttribute/Type.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Library</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

snippets/csharp/Microsoft.SqlServer.Server/SqlUserDefinedTypeAttribute/Type1.cs

@@ -36,13 +36,7 @@ public Int32 Y
         }
     }
 
-    public bool IsNull
-    {
-        get
-        {
-            return is_Null;
-        }
-    }
+    public bool IsNull => is_Null;
 
     public static Point Null
     {
@@ -74,12 +68,15 @@ public static Point Parse(SqlString s)
         }
 
         // Parse input string here to separate out coordinates
-        string str = Convert.ToString(s);
-        string[] xy = str.Split(':');
+        string? str = Convert.ToString(s);
+        string[]? xy = str?.Split(':');
 
         Point pt = new Point();
-        pt.X = Convert.ToInt32(xy[0]);
-        pt.Y = Convert.ToInt32(xy[1]);
+        if (xy is not null)
+        {
+            pt.X = Convert.ToInt32(xy[0]);
+            pt.Y = Convert.ToInt32(xy[1]);
+        }
         return (pt);
     }
 
@@ -125,9 +122,9 @@ public SqlString Quadrant()
 
 //-----------------------------------------------------------------------------
 //<Snippet12>
-[SqlUserDefinedType(Format.Native, MaxByteSize=8000)]
+[SqlUserDefinedType(Format.Native, MaxByteSize = 8000)]
 public class SampleType
 {
-   //...
+    //...
 }
 //</Snippet12>

snippets/csharp/System.Collections.Immutable/ImmutableArray`1/Overview/ImmutableArraySnippets.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
 </Project>

snippets/csharp/System.DateTime/Persistence.cs

@@ -1,10 +1,7 @@
-using DateTimeExtensions;
-using System;
+using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
-using System.Runtime.Serialization;
-using System.Runtime.Serialization.Formatters.Binary;
 using System.Threading;
 using System.Xml.Serialization;
 
@@ -29,13 +26,6 @@ public static void Snippets()
             File.Delete(filenameXml);
             PersistAsXML();
             File.Delete(filenameXml);
-
-            File.Delete(filenameBin);
-            PersistBinary();
-            File.Delete(filenameBin);
-
-            SaveDateWithTimeZone();
-            RestoreDateWithTimeZone();
         }
 
         // <Snippet1>
@@ -52,7 +42,7 @@ private static void SaveLocalDatesAsString()
                            new DateTime(2015, 1, 10, 1, 16, 0),
                            new DateTime(2014, 12, 20, 21, 45, 0),
                            new DateTime(2014, 6, 2, 15, 14, 0) };
-            string output = null;
+            string? output = null;
 
             Console.WriteLine($"Current Time Zone: {TimeZoneInfo.Local.DisplayName}");
             Console.WriteLine($"The dates on an {Thread.CurrentThread.CurrentCulture.Name} system:");
@@ -87,7 +77,7 @@ private static void RestoreLocalDatesFromString()
                 }
                 else
                 {
-                    Console.WriteLine("Cannot parse '{inputValue}'");
+                    Console.WriteLine($"Cannot parse '{inputValue}'");
                 }
             }
             Console.WriteLine("Restored dates...");
@@ -127,7 +117,7 @@ private static void SaveDatesAsInvariantStrings()
                            new DateTime(2015, 1, 10, 1, 16, 0),
                            new DateTime(2014, 12, 20, 21, 45, 0),
                            new DateTime(2014, 6, 2, 15, 14, 0) };
-            string output = null;
+            string? output = null;
 
             Console.WriteLine($"Current Time Zone: {TimeZoneInfo.Local.DisplayName}");
             Console.WriteLine($"The dates on an {Thread.CurrentThread.CurrentCulture.Name} system:");
@@ -318,29 +308,32 @@ public static void PersistAsXML()
             }
             catch (InvalidOperationException e)
             {
-                Console.WriteLine(e.InnerException.Message);
+                Console.WriteLine(e.InnerException?.Message);
             }
             finally
             {
                 if (sw != null) sw.Close();
             }
 
             // Deserialize the data.
-            DateTime[] deserializedDates;
+            DateTime[]? deserializedDates;
             using (var fs = new FileStream(filenameXml, FileMode.Open))
             {
-                deserializedDates = (DateTime[])serializer.Deserialize(fs);
+                deserializedDates = (DateTime[]?)serializer.Deserialize(fs);
             }
 
             // Display the dates.
             Console.WriteLine($"Leap year days from 2000-2100 on an {Thread.CurrentThread.CurrentCulture.Name} system:");
             int nItems = 0;
-            foreach (var dat in deserializedDates)
+            if (deserializedDates is not null)
             {
-                Console.Write($"   {dat:d}     ");
-                nItems++;
-                if (nItems % 5 == 0)
-                    Console.WriteLine();
+                foreach (var dat in deserializedDates)
+                {
+                    Console.Write($"   {dat:d}     ");
+                    nItems++;
+                    if (nItems % 5 == 0)
+                        Console.WriteLine();
+                }
             }
         }
         // The example displays the following output:
@@ -351,156 +344,5 @@ public static void PersistAsXML()
         //       29/02/2060       29/02/2064       29/02/2068       29/02/2072       29/02/2076
         //       29/02/2080       29/02/2084       29/02/2088       29/02/2092       29/02/2096
         // </Snippet4>
-
-        private const string filenameBin = @".\Dates.bin";
-
-        // <Snippet5>
-        public static void PersistBinary()
-        {
-            SaveDatesBinary();
-            RestoreDatesBinary();
-        }
-
-        private static void SaveDatesBinary()
-        {
-            DateTime[] dates = { new DateTime(2014, 6, 14, 6, 32, 0),
-                           new DateTime(2014, 7, 10, 23, 49, 0),
-                           new DateTime(2015, 1, 10, 1, 16, 0),
-                           new DateTime(2014, 12, 20, 21, 45, 0),
-                           new DateTime(2014, 6, 2, 15, 14, 0) };
-            var fs = new FileStream(filenameBin, FileMode.Create);
-            var bin = new BinaryFormatter();
-
-            Console.WriteLine($"Current Time Zone: {TimeZoneInfo.Local.DisplayName}");
-            Console.WriteLine($"The dates on an {Thread.CurrentThread.CurrentCulture.Name} system:");
-            for (int ctr = 0; ctr < dates.Length; ctr++)
-            {
-                Console.WriteLine(dates[ctr].ToString("f"));
-                dates[ctr] = dates[ctr].ToUniversalTime();
-            }
-            bin.Serialize(fs, dates);
-            fs.Close();
-            Console.WriteLine("Saved dates...");
-        }
-
-        private static void RestoreDatesBinary()
-        {
-            TimeZoneInfo.ClearCachedData();
-            Console.WriteLine($"Current Time Zone: {TimeZoneInfo.Local.DisplayName}");
-            Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture("en-GB");
-
-            FileStream fs = new FileStream(filenameBin, FileMode.Open);
-            BinaryFormatter bin = new BinaryFormatter();
-            var dates = (DateTime[])bin.Deserialize(fs);
-            fs.Close();
-
-            Console.WriteLine($"The dates on an {Thread.CurrentThread.CurrentCulture.Name} system:");
-            foreach (var value in dates)
-                Console.WriteLine(value.ToLocalTime().ToString("f"));
-
-            Console.WriteLine("Restored dates...");
-        }
-        // When saved on an en-US system, the example displays the following output:
-        //       Current Time Zone: (UTC-08:00) Pacific Time (US & Canada)
-        //       The dates on an en-US system:
-        //       Saturday, June 14, 2014 6:32 AM
-        //       Thursday, July 10, 2014 11:49 PM
-        //       Saturday, January 10, 2015 1:16 AM
-        //       Saturday, December 20, 2014 9:45 PM
-        //       Monday, June 02, 2014 3:14 PM
-        //       Saved dates...
-        //
-        // When restored on an en-GB system, the example displays the following output:
-        //       Current Time Zone: (UTC-6:00) Central Time (US & Canada)
-        //       The dates on an en-GB system:
-        //       14 June 2014 08:32
-        //       11 July 2014 01:49
-        //       10 January 2015 03:16
-        //       20 December 2014 23:45
-        //       02 June 2014 17:14
-        //       Restored dates...
-        // </Snippet5>
-
-        // <Snippet7>
-        public static void SaveDateWithTimeZone()
-        {
-            DateWithTimeZone[] dates = { new DateWithTimeZone(new DateTime(2014, 8, 9, 19, 30, 0),
-                                      TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time")),
-                                  new DateWithTimeZone(new DateTime(2014, 8, 15, 19, 0, 0),
-                                      TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time")),
-                                  new DateWithTimeZone(new DateTime(2014, 8, 22, 19, 30, 0),
-                                      TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time")),
-                                  new DateWithTimeZone(new DateTime(2014, 8, 28, 19, 0, 0),
-                                      TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time")) };
-            var fs = new FileStream(@".\Schedule.bin", FileMode.Create);
-            var formatter = new BinaryFormatter();
-            try
-            {
-                formatter.Serialize(fs, dates);
-                // Display dates.
-                foreach (var date in dates)
-                {
-                    TimeZoneInfo tz = date.TimeZone;
-                    Console.WriteLine($"{date.DateTime} {(tz.IsDaylightSavingTime(date.DateTime) ? tz.DaylightName : tz.StandardName)}");
-                }
-            }
-            catch (SerializationException e)
-            {
-                Console.WriteLine($"Serialization failed. Reason: {e.Message}");
-            }
-            finally
-            {
-                if (fs != null) fs.Close();
-            }
-        }
-        // The example displays the following output:
-        //       8/9/2014 7:30:00 PM Eastern Daylight Time
-        //       8/15/2014 7:00:00 PM Pacific Daylight Time
-        //       8/22/2014 7:30:00 PM Eastern Daylight Time
-        //       8/28/2014 7:00:00 PM Eastern Daylight Time
-        // </Snippet7>
-
-        // <Snippet8>
-        public static void RestoreDateWithTimeZone()
-        {
-            const string filename = @".\Schedule.bin";
-            FileStream fs;
-            if (File.Exists(filename))
-            {
-                fs = new FileStream(filename, FileMode.Open);
-            }
-            else
-            {
-                Console.WriteLine("Unable to find file to deserialize.");
-                return;
-            }
-
-            var formatter = new BinaryFormatter();
-            DateWithTimeZone[] dates;
-            try
-            {
-                dates = (DateWithTimeZone[])formatter.Deserialize(fs);
-                // Display dates.
-                foreach (var date in dates)
-                {
-                    TimeZoneInfo tz = date.TimeZone;
-                    Console.WriteLine($"{ date.DateTime} {(tz.IsDaylightSavingTime(date.DateTime) ? tz.DaylightName : tz.StandardName)}");
-                }
-            }
-            catch (SerializationException e)
-            {
-                Console.WriteLine($"Deserialization failed. Reason: {e.Message}");
-            }
-            finally
-            {
-                if (fs != null) fs.Close();
-            }
-        }
-        // The example displays the following output:
-        //       8/9/2014 7:30:00 PM Eastern Daylight Time
-        //       8/15/2014 7:00:00 PM Pacific Daylight Time
-        //       8/22/2014 7:30:00 PM Eastern Daylight Time
-        //       8/28/2014 7:00:00 PM Eastern Daylight Time
-        // </Snippet8>
     }
 }

snippets/csharp/System.DateTime/SystemDateTimeReference.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
 </Project>

snippets/csharp/System.Diagnostics.Tracing/EventSource/Overview/etwtracesmall.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <StartupObject>Demo.Program</StartupObject>
   </PropertyGroup>