Merge pull request #333 from AvaloniaUI/document-changed-event-ars

Pass the old new TextDocument on the DocumentChanged event

src/AvaloniaEdit/Document/DocumentChangedEventArgs.cs

@@ -0,0 +1,25 @@
+using System;
+
+namespace AvaloniaEdit.Document
+{
+    public class DocumentChangedEventArgs : EventArgs
+    {
+        /// <summary>
+        /// Gets the old TextDocument.
+        /// </summary>
+        public TextDocument OldDocument { get; private set; }
+        /// <summary>
+        /// Gets the new TextDocument.
+        /// </summary>
+        public TextDocument NewDocument { get; private set; }
+
+        /// <summary>
+        /// Provides data for the <see cref="ITextEditorComponent.DocumentChanged"/> event.
+        /// </summary>
+        public DocumentChangedEventArgs(TextDocument oldDocument, TextDocument newDocument)
+        {
+            OldDocument = oldDocument;
+            NewDocument = newDocument;
+        }
+    }
+}

src/AvaloniaEdit/Editing/TextArea.cs

@@ -258,7 +258,7 @@ public TextDocument Document
         }
 
         /// <inheritdoc/>
-        public event EventHandler DocumentChanged;
+        public event EventHandler<DocumentChangedEventArgs> DocumentChanged;
 
         /// <summary>
         /// Gets if the the document displayed by the text editor is readonly
@@ -296,7 +296,7 @@ private void OnDocumentChanged(TextDocument oldValue, TextDocument newValue)
             // in the new document (e.g. if new document is shorter than the old document).
             Caret.Location = new TextLocation(1, 1);
             ClearSelection();
-            DocumentChanged?.Invoke(this, EventArgs.Empty);
+            DocumentChanged?.Invoke(this, new DocumentChangedEventArgs(oldValue, newValue));
             //CommandManager.InvalidateRequerySuggested();
         }
         #endregion

src/AvaloniaEdit/Rendering/TextView.cs

@@ -130,7 +130,7 @@ internal FontFamily FontFamily
         /// <summary>
         /// Occurs when the document property has changed.
         /// </summary>
-        public event EventHandler DocumentChanged;
+        public event EventHandler<DocumentChangedEventArgs> DocumentChanged;
 
         private static void OnDocumentChanged(AvaloniaPropertyChangedEventArgs e)
         {
@@ -159,7 +159,7 @@ private void OnDocumentChanged(TextDocument oldValue, TextDocument newValue)
                 CachedElements = new TextViewCachedElements();
             }
             InvalidateMeasure();
-            DocumentChanged?.Invoke(this, EventArgs.Empty);
+            DocumentChanged?.Invoke(this, new DocumentChangedEventArgs(oldValue, newValue));
         }
 
         private void RecreateCachedElements()

src/AvaloniaEdit/TextEditor.cs

@@ -120,12 +120,12 @@ public TextDocument Document
         /// <summary>
         /// Occurs when the document property has changed.
         /// </summary>
-        public event EventHandler DocumentChanged;
+        public event EventHandler<DocumentChangedEventArgs> DocumentChanged;
 
         /// <summary>
         /// Raises the <see cref="DocumentChanged"/> event.
         /// </summary>
-        protected virtual void OnDocumentChanged(EventArgs e)
+        protected virtual void OnDocumentChanged(DocumentChangedEventArgs e)
         {
             DocumentChanged?.Invoke(this, e);
         }
@@ -148,7 +148,7 @@ private void OnDocumentChanged(TextDocument oldValue, TextDocument newValue)
                 TextDocumentWeakEventManager.TextChanged.AddHandler(newValue, OnTextChanged);
                 PropertyChangedWeakEventManager.AddHandler(newValue.UndoStack, OnUndoStackPropertyChangedHandler);
             }
-            OnDocumentChanged(EventArgs.Empty);
+            OnDocumentChanged(new DocumentChangedEventArgs(oldValue, newValue));
             OnTextChanged(EventArgs.Empty);
         }
         #endregion

src/AvaloniaEdit/TextEditorComponent.cs

@@ -39,7 +39,7 @@ public interface ITextEditorComponent : IServiceProvider
 		/// Occurs when the Document property changes (when the text editor is connected to another
 		/// document - not when the document content changes).
 		/// </summary>
-		event EventHandler DocumentChanged;
+		event EventHandler<DocumentChangedEventArgs> DocumentChanged;
 
 		/// <summary>
 		/// Gets the options of the text editor.