Handling of logical children is very weird in WPF...

fluentribbon · May 27, 2016 · 9733f78 · 9733f78
1 parent 4b3aa44
commit 9733f78
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Showing 3 changed files with 37 additions and 13 deletions.
diff --git a/Fluent.Ribbon.Showcase/TestWindow.xaml b/Fluent.Ribbon.Showcase/TestWindow.xaml
@@ -7,6 +7,7 @@
                      x:Name="window"
                      x:Class="FluentTest.TestWindow"
                      Title="{Binding DataContext.Title, ElementName=TestContent}"
+                     FlowDirection="LeftToRight"
                      Height="768"
                      Width="1024"
                      MinWidth="80"

diff --git a/Fluent.Ribbon/Controls/Backstage.cs b/Fluent.Ribbon/Controls/Backstage.cs
@@ -164,15 +164,29 @@ public UIElement Content
         /// This enables animation, styling, binding, etc...
         /// </summary>
         public static readonly DependencyProperty ContentProperty =
-            DependencyProperty.Register(nameof(Content), typeof(UIElement), typeof(Backstage), new UIPropertyMetadata(null));
+            DependencyProperty.Register(nameof(Content), typeof(UIElement), typeof(Backstage), new UIPropertyMetadata(null, OnContentChanged));
+
+        private static void OnContentChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        {
+            var backstage = (Backstage)d;
+            if (e.OldValue != null)
+            {
+                backstage.RemoveLogicalChild(e.OldValue);
+            }
+
+            if (e.NewValue != null)
+            {
+                backstage.AddLogicalChild(e.NewValue);
+            }
+        }
 
         #endregion
 
-        #region LogicalChildren
+        #region LogicalChildren 
 
-        /// <summary>
-        /// Gets an enumerator for logical child elements of this element.
-        /// </summary>
+        /// <summary> 
+        /// Gets an enumerator for logical child elements of this element. 
+        /// </summary> 
         protected override IEnumerator LogicalChildren
         {
             get

diff --git a/Fluent.Ribbon/Controls/Ribbon.cs b/Fluent.Ribbon/Controls/Ribbon.cs
@@ -444,7 +444,7 @@ public UIElement Menu
         /// This enables animation, styling, binding, etc...
         /// </summary>
         public static readonly DependencyProperty MenuProperty =
-            DependencyProperty.Register(nameof(Menu), typeof(UIElement), typeof(Ribbon), new UIPropertyMetadata(null));
+            DependencyProperty.Register(nameof(Menu), typeof(UIElement), typeof(Ribbon), new UIPropertyMetadata(null, AddOrRemoveLogicalChildOnPropertyChanged));
 
         #endregion
 
@@ -461,7 +461,7 @@ public StartScreen StartScreen
         /// <see cref="DependencyProperty"/> for <see cref="StartScreen"/>
         /// </summary>
         public static readonly DependencyProperty StartScreenProperty =
-            DependencyProperty.Register(nameof(StartScreen), typeof(StartScreen), typeof(Ribbon), new UIPropertyMetadata(null));
+            DependencyProperty.Register(nameof(StartScreen), typeof(StartScreen), typeof(Ribbon), new UIPropertyMetadata(null, AddOrRemoveLogicalChildOnPropertyChanged));
 
         /// <summary>
         /// Window title
@@ -498,7 +498,7 @@ public RibbonTabItem SelectedTabItem
         /// Using a DependencyProperty as the backing store for SelectedTabItem.  This enables animation, styling, binding, etc...
         /// </summary>
         public static readonly DependencyProperty SelectedTabItemProperty =
-            DependencyProperty.Register("SelectedTabItem", typeof(RibbonTabItem), typeof(Ribbon), new UIPropertyMetadata(null, OnSelectedTabItemChanged));
+            DependencyProperty.Register(nameof(SelectedTabItem), typeof(RibbonTabItem), typeof(Ribbon), new UIPropertyMetadata(null, OnSelectedTabItemChanged));
 
         private static void OnSelectedTabItemChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {
@@ -557,6 +557,20 @@ private static void OnSelectedTabIndexChanged(DependencyObject d, DependencyProp
             }
         }
 
+        private static void AddOrRemoveLogicalChildOnPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        {
+            var ribbon = (Ribbon)d;
+            if (e.OldValue != null)
+            {
+                ribbon.RemoveLogicalChild(e.OldValue);
+            }
+
+            if (e.NewValue != null)
+            {
+                ribbon.AddLogicalChild(e.NewValue);
+            }
+        }
+
         /// <summary>
         /// Gets the first visible TabItem
         /// </summary>
@@ -813,11 +827,6 @@ protected override IEnumerator LogicalChildren
                     yield return this.layoutRoot;
                 }
 
-                if (this.Menu != null)
-                {
-                    yield return this.Menu;
-                }
-
                 if (this.StartScreen != null)
                 {
                     yield return this.StartScreen;