Use ReadOnlyCollection.Empty (#10013)

ThomasGoulet73 · web-flow · commit e8455dc12847 · 2025-02-19T11:21:00.000+05:30
* Use ReadOnlyCollection.Empty

* Replace EmptyList with ReadOnlyCollection.Empty

* Revert TextBlock.cs changes
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/ManipulationDevice.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/ManipulationDevice.cs
@@ -209,7 +209,7 @@ internal IEnumerable<IManipulator> GetManipulatorsReadOnly()
             }
             else
             {
-                return new ReadOnlyCollection<IManipulator>(new List<IManipulator>(2));
+                return ReadOnlyCollection<IManipulator>.Empty;
             }
         }
 
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/ContainerParaClient.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/ContainerParaClient.cs
@@ -330,7 +330,7 @@ internal ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out boo
 
             if (subtrackDetails.cParas == 0) 
             {
-                return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));
+                return ReadOnlyCollection<ParagraphResult>.Empty;
             }
 
             // Get list of paragraphs
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/FigureParaClient.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/FigureParaClient.cs
@@ -569,7 +569,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool
 
                 if (trackDetails.cParas == 0) 
                 {
-                    return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));  
+                    return ReadOnlyCollection<ParagraphResult>.Empty;  
                 }
 
                 // Get list of paragraphs
@@ -595,7 +595,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool
                 // cBasicColumns == 0, means that subpage content is empty
                 if (subpageDetails.u.complex.cBasicColumns == 0) 
                 {
-                    return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));
+                    return ReadOnlyCollection<ParagraphResult>.Empty;
                 }
 
                 // Retrieve description for each column.
@@ -609,7 +609,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool
 
                 if (trackDetails.cParas == 0) 
                 {
-                    return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));
+                    return ReadOnlyCollection<ParagraphResult>.Empty;
                 }
 
                 // Get list of paragraphs
@@ -736,7 +736,7 @@ internal Geometry GetTightBoundingGeometryFromTextPositions(ReadOnlyCollection<C
             // Figure always has one column, so we can skip getting a column from the text position range
             Invariant.Assert(columns != null && columns.Count <= 1, "Columns collection is null.");
             Invariant.Assert(floatingElements != null, "Floating element collection is null.");
-            ReadOnlyCollection<ParagraphResult> paragraphs = (columns.Count > 0) ? columns[0].Paragraphs : new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));
+            ReadOnlyCollection<ParagraphResult> paragraphs = (columns.Count > 0) ? columns[0].Paragraphs : ReadOnlyCollection<ParagraphResult>.Empty;
 
             if (paragraphs.Count > 0 || floatingElements.Count > 0)
             {
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/FloaterParaClient.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/FloaterParaClient.cs
@@ -578,7 +578,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool
 
                 if (trackDetails.cParas == 0) 
                 {
-                    return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));  
+                    return ReadOnlyCollection<ParagraphResult>.Empty;  
                 }
 
                 // Get list of paragraphs
@@ -604,7 +604,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool
                 // cBasicColumns == 0, means that subpage content is empty
                 if (subpageDetails.u.complex.cBasicColumns == 0) 
                 {
-                    return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));
+                    return ReadOnlyCollection<ParagraphResult>.Empty;
                 }
 
                 // Retrieve description for each column.
@@ -618,7 +618,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool
 
                 if (trackDetails.cParas == 0) 
                 {
-                    return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));
+                    return ReadOnlyCollection<ParagraphResult>.Empty;
                 }
 
                 // Get list of paragraphs
@@ -745,7 +745,7 @@ internal Geometry GetTightBoundingGeometryFromTextPositions(ReadOnlyCollection<C
             // Floater always has one column, so we can skip getting a column from the text position range
             Invariant.Assert(columns != null && columns.Count <= 1, "Columns collection is null.");
             Invariant.Assert(floatingElements != null, "Floating element collection is null.");
-            ReadOnlyCollection<ParagraphResult> paragraphs = (columns.Count > 0) ? columns[0].Paragraphs : new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));
+            ReadOnlyCollection<ParagraphResult> paragraphs = (columns.Count > 0) ? columns[0].Paragraphs : ReadOnlyCollection<ParagraphResult>.Empty;
 
             if (paragraphs.Count > 0 || floatingElements.Count > 0)
             {
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/FlowDocumentPage.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/FlowDocumentPage.cs
@@ -367,7 +367,7 @@ internal IEnumerator<IInputElement> HostedElementsCore
                 else
                 {
                     // Return empty collection
-                    return new HostedElements(new ReadOnlyCollection<TextSegment>(new List<TextSegment>(0)));
+                    return new HostedElements(ReadOnlyCollection<TextSegment>.Empty);
                 }
             }
         }
@@ -572,7 +572,7 @@ internal ReadOnlyCollection<ParagraphResult> GetParagraphResultsFromColumn(IntPt
 
             if (trackDetails.cParas == 0)
             {
-                return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));
+                return ReadOnlyCollection<ParagraphResult>.Empty;
             }
 
             PTS.FSPARADESCRIPTION[] arrayParaDesc;
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/PageVisual.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/PageVisual.cs
@@ -124,7 +124,7 @@ ReadOnlyCollection<Rect> IContentHost.GetRectangles(ContentElement child)
             {
                 return host.GetRectangles(child);
             }
-            return new ReadOnlyCollection<Rect>(new List<Rect>(0));
+            return ReadOnlyCollection<Rect>.Empty;
         }
 
         /// <summary>
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/TextParaClient.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/PtsHost/TextParaClient.cs
@@ -339,7 +339,7 @@ internal ReadOnlyCollection<LineResult> GetLineResults()
 #if TEXTPANELLAYOUTDEBUG
             TextPanelDebug.IncrementCounter("TextPara.GetLines", TextPanelDebug.Category.TextView);
 #endif
-            ReadOnlyCollection<LineResult> lines = new ReadOnlyCollection<LineResult>(new List<LineResult>(0));
+            ReadOnlyCollection<LineResult> lines = ReadOnlyCollection<LineResult>.Empty;
 
             // Query paragraph details
             PTS.FSTEXTDETAILS textDetails;
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/documents/DocumentPageTextView.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/documents/DocumentPageTextView.cs
@@ -313,7 +313,7 @@ internal override ReadOnlyCollection<GlyphRun> GetGlyphRuns(ITextPointer start,
             }
             if (IsPageMissing)
             {
-                return new ReadOnlyCollection<GlyphRun>(new List<GlyphRun>());
+                return ReadOnlyCollection<GlyphRun>.Empty;
             }
             return _pageTextView.GetGlyphRuns(start, end);
         }
@@ -528,7 +528,7 @@ internal override ReadOnlyCollection<TextSegment> TextSegments
             {
                 if (!IsValid || IsPageMissing)
                 {
-                    return new ReadOnlyCollection<TextSegment>(new List<TextSegment>());
+                    return ReadOnlyCollection<TextSegment>.Empty;
                 }
                 return _pageTextView.TextSegments;
             }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/documents/TextDocumentView.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/documents/TextDocumentView.cs
@@ -588,7 +588,7 @@ internal override ReadOnlyCollection<TextSegment> TextSegments
                 // Verify that layout information is valid. Cannot continue if not valid.
                 if (!IsValid)
                 {
-                    return new ReadOnlyCollection<TextSegment>(new List<TextSegment>());
+                    return ReadOnlyCollection<TextSegment>.Empty;
                 }
                 return this.TextSegmentsCore;
             }
@@ -3515,7 +3515,7 @@ private Rect GetRectangleFromContentEdge(ParagraphResult paragraphResult, ITextP
         /// <summary>
         /// Cached collection of ColumnResults.
         /// </summary>
-        private static ReadOnlyCollection<ParagraphResult> _emptyParagraphCollection = new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));
+        private static ReadOnlyCollection<ParagraphResult> _emptyParagraphCollection = ReadOnlyCollection<ParagraphResult>.Empty;
 
         /// <summary>
         /// Cached collection of TextSegments.
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/documents/TextViewBase.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/documents/TextViewBase.cs
@@ -109,7 +109,7 @@ internal virtual ReadOnlyCollection<GlyphRun> GetGlyphRuns(ITextPointer start, I
             {
                 throw new InvalidOperationException(SR.TextViewInvalidLayout);
             }
-            return new ReadOnlyCollection<GlyphRun>(new List<GlyphRun>());
+            return ReadOnlyCollection<GlyphRun>.Empty;
         }
 
         /// <summary>
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/documents/UIElementIsland.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/documents/UIElementIsland.cs
@@ -195,7 +195,7 @@ IInputElement IContentHost.InputHitTest(Point point)
         /// </summary>
         ReadOnlyCollection<Rect> IContentHost.GetRectangles(ContentElement child)
         {
-            return new ReadOnlyCollection<Rect>(new List<Rect>());
+            return ReadOnlyCollection<Rect>.Empty;
         }
 
         /// <summary>
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Annotations/AnnotationDocumentPaginator.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Annotations/AnnotationDocumentPaginator.cs
@@ -451,7 +451,7 @@ public IEnumerator<IInputElement> HostedElements
                     }
                     else
                     {
-                        return new HostedElements(new ReadOnlyCollection<TextSegment>(new List<TextSegment>(0)));
+                        return new HostedElements(ReadOnlyCollection<TextSegment>.Empty);
                     }
                 }
             }
@@ -467,7 +467,7 @@ public ReadOnlyCollection<Rect> GetRectangles(ContentElement child)
                 }
                 else
                 {
-                    return new ReadOnlyCollection<Rect>(new List<Rect>(0));
+                    return ReadOnlyCollection<Rect>.Empty;
                 }
             }
 
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DocumentViewer.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/DocumentViewer.cs
@@ -1177,7 +1177,7 @@ protected override ReadOnlyCollection<DocumentPageView> GetPageViewsCollection(o
             else
             {
                 //Return an empty collection (null is not valid).
-                pageViews = new ReadOnlyCollection<DocumentPageView>(new List<DocumentPageView>(0));
+                pageViews = ReadOnlyCollection<DocumentPageView>.Empty;
             }
 
             return pageViews;
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Primitives/DocumentViewerBase.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Primitives/DocumentViewerBase.cs
@@ -59,7 +59,7 @@ static DocumentViewerBase()
         protected DocumentViewerBase()
             : base()
         {
-            _pageViews = new ReadOnlyCollection<DocumentPageView>(new List<DocumentPageView>());
+            _pageViews = ReadOnlyCollection<DocumentPageView>.Empty;
             // By default text selection is enabled.
             SetFlags(true, Flags.IsSelectionEnabled);
         }
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/TextChangedEventArgs.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/TextChangedEventArgs.cs
@@ -86,7 +86,7 @@ public TextChangedEventArgs(RoutedEvent id, UndoAction action, ICollection<TextC
         /// <param name="id">event id</param>
         /// <param name="action">UndoAction</param>
         public TextChangedEventArgs(RoutedEvent id, UndoAction action)
-            : this(id, action, new ReadOnlyCollection<TextChange>(new List<TextChange>()))
+            : this(id, action, ReadOnlyCollection<TextChange>.Empty)
         {
         }
 
diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/TextFlow.cs b/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/TextFlow.cs
@@ -989,7 +989,7 @@ protected virtual ReadOnlyCollection<Rect> GetRectanglesCore(ContentElement chil
                 throw new ArgumentNullException("child");
             }
 
-            ReadOnlyCollection<Rect> rectangles = new ReadOnlyCollection<Rect>(new List<Rect>(0));
+            ReadOnlyCollection<Rect> rectangles = ReadOnlyCollection<Rect>.Empty;
             if (IsLayoutDataValid)
             {
                 // Here we must call the internal function on document page that tells it whether or not
@@ -1019,7 +1019,7 @@ protected virtual IEnumerator<IInputElement> HostedElementsCore
                 else
                 {
                     // Return empty collection
-                    hostedElements = new HostedElements(new ReadOnlyCollection<TextSegment>(new List<TextSegment>(0)));
+                    hostedElements = new HostedElements(ReadOnlyCollection<TextSegment>.Empty);
                 }
                 return hostedElements;
             }
diff --git a/src/Microsoft.DotNet.Wpf/src/System.Xaml/System/Xaml/Schema/MemberReflector.cs b/src/Microsoft.DotNet.Wpf/src/System.Xaml/System/Xaml/Schema/MemberReflector.cs
@@ -4,6 +4,7 @@
 
 #nullable disable
 
+using System.Collections.ObjectModel;
 using System.ComponentModel;
 using System.Reflection;
 using System.Windows.Markup;
@@ -94,7 +95,7 @@ internal static MemberReflector UnknownReflector
                     s_UnknownReflector._typeConverter.Value = null;
                     s_UnknownReflector._valueSerializer.Value = null;
 
-                    s_UnknownReflector.DependsOn = XamlType.EmptyList<XamlMember>.Value;
+                    s_UnknownReflector.DependsOn = ReadOnlyCollection<XamlMember>.Empty;
                     s_UnknownReflector.Invoker = XamlMemberInvoker.UnknownInvoker;
                     s_UnknownReflector.Type = XamlLanguage.Object;
                 }
diff --git a/src/Microsoft.DotNet.Wpf/src/System.Xaml/System/Xaml/XamlMember.cs b/src/Microsoft.DotNet.Wpf/src/System.Xaml/System/Xaml/XamlMember.cs
@@ -4,6 +4,7 @@
 
 #nullable disable
 
+using System.Collections.ObjectModel;
 using System.ComponentModel;
 using System.Reflection;
 using System.Threading;
@@ -358,7 +359,7 @@ public IList<XamlMember> DependsOn
                 EnsureReflector();
                 if (_reflector.DependsOn is null)
                 {
-                    _reflector.DependsOn = LookupDependsOn() ?? XamlType.EmptyList<XamlMember>.Value;
+                    _reflector.DependsOn = LookupDependsOn() ?? ReadOnlyCollection<XamlMember>.Empty;
                 }
 
                 return _reflector.DependsOn;
diff --git a/src/Microsoft.DotNet.Wpf/src/System.Xaml/System/Xaml/XamlType.cs b/src/Microsoft.DotNet.Wpf/src/System.Xaml/System/Xaml/XamlType.cs
@@ -243,7 +243,7 @@ public IList<XamlType> AllowedContentTypes
                 if (_reflector.AllowedContentTypes is null)
                 {
                     _reflector.AllowedContentTypes = LookupAllowedContentTypes() ??
-                        EmptyList<XamlType>.Value;
+                        ReadOnlyCollection<XamlType>.Empty;
                 }
 
                 return _reflector.AllowedContentTypes;
@@ -263,7 +263,7 @@ public IList<XamlType> ContentWrappers
                 if (_reflector.ContentWrappers is null)
                 {
                     _reflector.ContentWrappers = LookupContentWrappers() ??
-                        EmptyList<XamlType>.Value;
+                        ReadOnlyCollection<XamlType>.Empty;
                 }
 
                 return _reflector.ContentWrappers;
@@ -635,7 +635,7 @@ internal ICollection<XamlMember> GetAllExcludedReadOnlyMembers()
             EnsureReflector();
             if (_reflector.ExcludedReadOnlyMembers is null)
             {
-                _reflector.ExcludedReadOnlyMembers = LookupAllExcludedReadOnlyMembers() ?? EmptyList<XamlMember>.Value;
+                _reflector.ExcludedReadOnlyMembers = LookupAllExcludedReadOnlyMembers() ?? ReadOnlyCollection<XamlMember>.Empty;
             }
 
             return _reflector.ExcludedReadOnlyMembers;
@@ -647,7 +647,7 @@ internal IEnumerable<ConstructorInfo> GetConstructors()
         {
             if (UnderlyingType is null)
             {
-                return EmptyList<ConstructorInfo>.Value;
+                return ReadOnlyCollection<ConstructorInfo>.Empty;
             }
 
             if (IsPublic)
@@ -725,7 +725,7 @@ protected virtual XamlMember LookupAliasedProperty(XamlDirective directive)
 
         protected virtual IList<XamlType> LookupAllowedContentTypes()
         {
-            IList<XamlType> contentWrappers = ContentWrappers ?? EmptyList<XamlType>.Value;
+            IList<XamlType> contentWrappers = ContentWrappers ?? ReadOnlyCollection<XamlType>.Empty;
             List<XamlType> result = new List<XamlType>(contentWrappers.Count + 1);
             result.Add(ItemType);
 
@@ -1571,7 +1571,7 @@ internal static ReadOnlyCollection<T> GetReadOnly<T>(IList<T> list)
                 return new ReadOnlyCollection<T>(list);
             }
 
-            return EmptyList<T>.Value;
+            return ReadOnlyCollection<T>.Empty;
         }
 
         private static ReadOnlyCollection<XamlType> GetTypeArguments(IList<XamlType> typeArguments)
@@ -1957,11 +1957,5 @@ private static bool TypeArgumentsAreEqual(XamlType xamlType1, XamlType xamlType2
         }
 
         #endregion
-
-        internal static class EmptyList<T>
-        {
-            public static readonly ReadOnlyCollection<T> Value =
-                new ReadOnlyCollection<T>(Array.Empty<T>());
-        }
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -209,7 +209,7 @@ internal IEnumerable<IManipulator> GetManipulatorsReadOnly()`
`209`	`209`	`}`
`210`	`210`	`else`
`211`	`211`	`{`
`212`		`- return new ReadOnlyCollection<IManipulator>(new List<IManipulator>(2));`
	`212`	`+ return ReadOnlyCollection<IManipulator>.Empty;`
`213`	`213`	`}`
`214`	`214`	`}`
`215`	`215`
Original file line number	Diff line number	Diff line change
`@@ -330,7 +330,7 @@ internal ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out boo`
`330`	`330`
`331`	`331`	`if (subtrackDetails.cParas == 0)`
`332`	`332`	`{`
`333`		`- return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`333`	`+ return ReadOnlyCollection<ParagraphResult>.Empty;`
`334`	`334`	`}`
`335`	`335`
`336`	`336`	`// Get list of paragraphs`
Original file line number	Diff line number	Diff line change
`@@ -569,7 +569,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool`
`569`	`569`
`570`	`570`	`if (trackDetails.cParas == 0)`
`571`	`571`	`{`
`572`		`- return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`572`	`+ return ReadOnlyCollection<ParagraphResult>.Empty;`
`573`	`573`	`}`
`574`	`574`
`575`	`575`	`// Get list of paragraphs`
`@@ -595,7 +595,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool`
`595`	`595`	`// cBasicColumns == 0, means that subpage content is empty`
`596`	`596`	`if (subpageDetails.u.complex.cBasicColumns == 0)`
`597`	`597`	`{`
`598`		`- return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`598`	`+ return ReadOnlyCollection<ParagraphResult>.Empty;`
`599`	`599`	`}`
`600`	`600`
`601`	`601`	`// Retrieve description for each column.`
`@@ -609,7 +609,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool`
`609`	`609`
`610`	`610`	`if (trackDetails.cParas == 0)`
`611`	`611`	`{`
`612`		`- return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`612`	`+ return ReadOnlyCollection<ParagraphResult>.Empty;`
`613`	`613`	`}`
`614`	`614`
`615`	`615`	`// Get list of paragraphs`
`@@ -736,7 +736,7 @@ internal Geometry GetTightBoundingGeometryFromTextPositions(ReadOnlyCollection<C`
`736`	`736`	`// Figure always has one column, so we can skip getting a column from the text position range`
`737`	`737`	`Invariant.Assert(columns != null && columns.Count <= 1, "Columns collection is null.");`
`738`	`738`	`Invariant.Assert(floatingElements != null, "Floating element collection is null.");`
`739`		`- ReadOnlyCollection<ParagraphResult> paragraphs = (columns.Count > 0) ? columns[0].Paragraphs : new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`739`	`+ ReadOnlyCollection<ParagraphResult> paragraphs = (columns.Count > 0) ? columns[0].Paragraphs : ReadOnlyCollection<ParagraphResult>.Empty;`
`740`	`740`
`741`	`741`	`if (paragraphs.Count > 0 \|\| floatingElements.Count > 0)`
`742`	`742`	`{`
Original file line number	Diff line number	Diff line change
`@@ -578,7 +578,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool`
`578`	`578`
`579`	`579`	`if (trackDetails.cParas == 0)`
`580`	`580`	`{`
`581`		`- return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`581`	`+ return ReadOnlyCollection<ParagraphResult>.Empty;`
`582`	`582`	`}`
`583`	`583`
`584`	`584`	`// Get list of paragraphs`
`@@ -604,7 +604,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool`
`604`	`604`	`// cBasicColumns == 0, means that subpage content is empty`
`605`	`605`	`if (subpageDetails.u.complex.cBasicColumns == 0)`
`606`	`606`	`{`
`607`		`- return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`607`	`+ return ReadOnlyCollection<ParagraphResult>.Empty;`
`608`	`608`	`}`
`609`	`609`
`610`	`610`	`// Retrieve description for each column.`
`@@ -618,7 +618,7 @@ private ReadOnlyCollection<ParagraphResult> GetChildrenParagraphResults(out bool`
`618`	`618`
`619`	`619`	`if (trackDetails.cParas == 0)`
`620`	`620`	`{`
`621`		`- return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`621`	`+ return ReadOnlyCollection<ParagraphResult>.Empty;`
`622`	`622`	`}`
`623`	`623`
`624`	`624`	`// Get list of paragraphs`
`@@ -745,7 +745,7 @@ internal Geometry GetTightBoundingGeometryFromTextPositions(ReadOnlyCollection<C`
`745`	`745`	`// Floater always has one column, so we can skip getting a column from the text position range`
`746`	`746`	`Invariant.Assert(columns != null && columns.Count <= 1, "Columns collection is null.");`
`747`	`747`	`Invariant.Assert(floatingElements != null, "Floating element collection is null.");`
`748`		`- ReadOnlyCollection<ParagraphResult> paragraphs = (columns.Count > 0) ? columns[0].Paragraphs : new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`748`	`+ ReadOnlyCollection<ParagraphResult> paragraphs = (columns.Count > 0) ? columns[0].Paragraphs : ReadOnlyCollection<ParagraphResult>.Empty;`
`749`	`749`
`750`	`750`	`if (paragraphs.Count > 0 \|\| floatingElements.Count > 0)`
`751`	`751`	`{`
Original file line number	Diff line number	Diff line change
`@@ -367,7 +367,7 @@ internal IEnumerator<IInputElement> HostedElementsCore`
`367`	`367`	`else`
`368`	`368`	`{`
`369`	`369`	`// Return empty collection`
`370`		`- return new HostedElements(new ReadOnlyCollection<TextSegment>(new List<TextSegment>(0)));`
	`370`	`+ return new HostedElements(ReadOnlyCollection<TextSegment>.Empty);`
`371`	`371`	`}`
`372`	`372`	`}`
`373`	`373`	`}`
`@@ -572,7 +572,7 @@ internal ReadOnlyCollection<ParagraphResult> GetParagraphResultsFromColumn(IntPt`
`572`	`572`
`573`	`573`	`if (trackDetails.cParas == 0)`
`574`	`574`	`{`
`575`		`- return new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`575`	`+ return ReadOnlyCollection<ParagraphResult>.Empty;`
`576`	`576`	`}`
`577`	`577`
`578`	`578`	`PTS.FSPARADESCRIPTION[] arrayParaDesc;`
Original file line number	Diff line number	Diff line change
`@@ -124,7 +124,7 @@ ReadOnlyCollection<Rect> IContentHost.GetRectangles(ContentElement child)`
`124`	`124`	`{`
`125`	`125`	`return host.GetRectangles(child);`
`126`	`126`	`}`
`127`		`- return new ReadOnlyCollection<Rect>(new List<Rect>(0));`
	`127`	`+ return ReadOnlyCollection<Rect>.Empty;`
`128`	`128`	`}`
`129`	`129`
`130`	`130`	`/// <summary>`
Original file line number	Diff line number	Diff line change
`@@ -313,7 +313,7 @@ internal override ReadOnlyCollection<GlyphRun> GetGlyphRuns(ITextPointer start,`
`313`	`313`	`}`
`314`	`314`	`if (IsPageMissing)`
`315`	`315`	`{`
`316`		`- return new ReadOnlyCollection<GlyphRun>(new List<GlyphRun>());`
	`316`	`+ return ReadOnlyCollection<GlyphRun>.Empty;`
`317`	`317`	`}`
`318`	`318`	`return _pageTextView.GetGlyphRuns(start, end);`
`319`	`319`	`}`
`@@ -528,7 +528,7 @@ internal override ReadOnlyCollection<TextSegment> TextSegments`
`528`	`528`	`{`
`529`	`529`	`if (!IsValid \|\| IsPageMissing)`
`530`	`530`	`{`
`531`		`- return new ReadOnlyCollection<TextSegment>(new List<TextSegment>());`
	`531`	`+ return ReadOnlyCollection<TextSegment>.Empty;`
`532`	`532`	`}`
`533`	`533`	`return _pageTextView.TextSegments;`
`534`	`534`	`}`
Original file line number	Diff line number	Diff line change
`@@ -588,7 +588,7 @@ internal override ReadOnlyCollection<TextSegment> TextSegments`
`588`	`588`	`// Verify that layout information is valid. Cannot continue if not valid.`
`589`	`589`	`if (!IsValid)`
`590`	`590`	`{`
`591`		`- return new ReadOnlyCollection<TextSegment>(new List<TextSegment>());`
	`591`	`+ return ReadOnlyCollection<TextSegment>.Empty;`
`592`	`592`	`}`
`593`	`593`	`return this.TextSegmentsCore;`
`594`	`594`	`}`
`@@ -3515,7 +3515,7 @@ private Rect GetRectangleFromContentEdge(ParagraphResult paragraphResult, ITextP`
`3515`	`3515`	`/// <summary>`
`3516`	`3516`	`/// Cached collection of ColumnResults.`
`3517`	`3517`	`/// </summary>`
`3518`		`- private static ReadOnlyCollection<ParagraphResult> _emptyParagraphCollection = new ReadOnlyCollection<ParagraphResult>(new List<ParagraphResult>(0));`
	`3518`	`+ private static ReadOnlyCollection<ParagraphResult> _emptyParagraphCollection = ReadOnlyCollection<ParagraphResult>.Empty;`
`3519`	`3519`
`3520`	`3520`	`/// <summary>`
`3521`	`3521`	`/// Cached collection of TextSegments.`
Original file line number	Diff line number	Diff line change
`@@ -109,7 +109,7 @@ internal virtual ReadOnlyCollection<GlyphRun> GetGlyphRuns(ITextPointer start, I`
`109`	`109`	`{`
`110`	`110`	`throw new InvalidOperationException(SR.TextViewInvalidLayout);`
`111`	`111`	`}`
`112`		`- return new ReadOnlyCollection<GlyphRun>(new List<GlyphRun>());`
	`112`	`+ return ReadOnlyCollection<GlyphRun>.Empty;`
`113`	`113`	`}`
`114`	`114`
`115`	`115`	`/// <summary>`