Add a RootPart property to OpenXmlPackage (#661)

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Include symbols support for debugging (#650)
 - Exposed `IXmlNamespaceResolver` from `XmlPath` instead of formatted list of strings to expose namespace/prefix mapping (#536)
 - Implemented `IComparable<T>` and `IEquatable<T>` on `OpenXmlComparableSimpleValue` to allow comparisons without boxing (#550)
+- Added `OpenXmlPackage.RootPart` to easily access the root part on any package (#661)
 
 ### Changes
 - Updated to v4.7.0 of System.IO.Packaging which brings in a number of perf fixes (#660)

src/DocumentFormat.OpenXml/Packaging/OpenXmlPackage.cs

@@ -34,6 +34,11 @@ protected OpenXmlPackage()
         {
         }
 
+        /// <summary>
+        /// Gets the root part for the package.
+        /// </summary>
+        public virtual OpenXmlPart RootPart => throw new InvalidDataException(ExceptionMessages.UnknownPackage);
+
         /// <summary>
         /// Initializes a new instance of the OpenXmlPackage class using the supplied Open XML package.
         /// </summary>

src/DocumentFormat.OpenXml/Packaging/PresentationDocument.cs

@@ -651,6 +651,9 @@ public WebExTaskpanesPart AddWebExTaskpanesPart()
             return childPart;
         }
 
+        /// <inheritdoc />
+        public override OpenXmlPart RootPart => PresentationPart;
+
         /// <summary>
         /// Gets the PresentationPart of the PresentationDocument.
         /// </summary>

src/DocumentFormat.OpenXml/Packaging/SpreadsheetDocument.cs

@@ -651,6 +651,9 @@ public WebExTaskpanesPart AddWebExTaskpanesPart()
             return childPart;
         }
 
+        /// <inheritdoc />
+        public override OpenXmlPart RootPart => WorkbookPart;
+
         /// <summary>
         /// Gets the WorkbookPart of the SpreadsheetDocument.
         /// </summary>

src/DocumentFormat.OpenXml/Packaging/WordprocessingDocument.cs

@@ -692,6 +692,9 @@ public WebExTaskpanesPart AddWebExTaskpanesPart()
             return childPart;
         }
 
+        /// <inheritdoc />
+        public override OpenXmlPart RootPart => MainDocumentPart;
+
         /// <summary>
         /// Gets the MainDocumentPart of the WordprocessingDocument.
         /// </summary>

src/DocumentFormat.OpenXml/Validation/DocumentValidator.cs

@@ -131,37 +131,12 @@ private void ValidatePart(OpenXmlPart part, ValidationContext context)
             }
         }
 
-        private static OpenXmlPart GetMainPart(OpenXmlPackage package)
-        {
-            if (package is null)
-            {
-                throw new ArgumentNullException(nameof(package));
-            }
-
-            if (package is WordprocessingDocument word)
-            {
-                return word.MainDocumentPart;
-            }
-            else if (package is SpreadsheetDocument spreadsheet)
-            {
-                return spreadsheet.WorkbookPart;
-            }
-            else if (package is PresentationDocument presentation)
-            {
-                return presentation.PresentationPart;
-            }
-            else
-            {
-                throw new System.IO.InvalidDataException(ExceptionMessages.UnknownPackage);
-            }
-        }
-
         /// <summary>
         /// Gets all the parts needs to be validated.
         /// </summary>
         private IEnumerable<OpenXmlPart> PartsToBeValidated(OpenXmlPackage package)
         {
-            var mainPart = GetMainPart(package);
+            var mainPart = package.RootPart;
             if (mainPart != null)
             {
                 var parts = new Dictionary<OpenXmlPart, bool>();