fix issue #85

punker76 · Feb 12, 2014 · 9f3dec4 · 9f3dec4
1 parent 2a6c014
commit 9f3dec4
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Showing 4 changed files with 79 additions and 23 deletions.
diff --git a/Examples/DefaultsExample/Data.cs b/Examples/DefaultsExample/Data.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 using System.Text;
 using System.Collections.ObjectModel;
@@ -13,6 +14,20 @@
 
 namespace DefaultsExample
 {
+  public class CustomDropHandlerForIssue85 : IDropTarget
+  {
+    public void DragOver(IDropInfo dropInfo)
+    {
+      dropInfo.Effects = DragDropEffects.Copy;
+    }
+
+    public void Drop(IDropInfo dropInfo)
+    {
+      MessageBox.Show("He, now it works :-D");
+      ((TextBox)dropInfo.VisualTarget).Text = (string)dropInfo.Data;
+    }
+  }
+
   internal class Data : IDropTarget
   {
     public Data()
@@ -23,6 +38,8 @@ public Data()
       this.CustomCollection1 = new ObservableCollection<CustomDataModel>();
       this.CustomCollection2 = new ObservableCollection<CustomDataModel>();
 
+      this.CustomDropHandler = new CustomDropHandlerForIssue85();
+
       for (var n = 0; n < 100; ++n) {
         this.Collection1.Add("Item " + n);
         this.CustomCollection1.Add(new CustomDataModel { Name = "Custom Item " + n });
@@ -58,6 +75,8 @@ public Data()
     public ObservableCollection<GroupedItem> GroupedCollection { get; private set; }
     public ObservableCollection<TreeNode> TreeCollection { get; private set; }
 
+    public CustomDropHandlerForIssue85 CustomDropHandler { get; private set; }
+
     //
     // The drop handler is only used for the grouping example.
     //

diff --git a/Examples/DefaultsExample/Window(NET4).xaml b/Examples/DefaultsExample/Window(NET4).xaml
@@ -621,7 +621,7 @@
                  ItemTemplate="{StaticResource CustomTemplate}"
                  dd:DragDrop.IsDragSource="True"
                  dd:DragDrop.IsDropTarget="True"
-                 dd:DragDrop.DragAdornerTemplate="{StaticResource DragAdorner}" />
+                 dd:DragDrop.DragAdornerTemplate="{StaticResource CustomTemplate}" />
       </Grid>
     </TabItem>
 
@@ -855,5 +855,24 @@
           ItemsSource="{Binding Collection3}" />
       </Grid>
     </TabItem>
+
+    <TabItem Header="Drop to TextBox, issue #85">
+      <Grid>
+        <Grid.ColumnDefinitions>
+          <ColumnDefinition Width="*" />
+          <ColumnDefinition Width="*" />
+        </Grid.ColumnDefinitions>
+        <TextBlock Grid.ColumnSpan="2">This example uses a DataTemplateSelector for the drag adorner.</TextBlock>
+        <ListBox ItemsSource="{Binding Collection1}"
+                 Grid.Column="0"
+                 dd:DragDrop.IsDragSource="True"></ListBox>
+        <TextBox Text="Drop the item here"
+                 IsReadOnly="True"
+                 Grid.Column="1"
+                 Height="30"
+                 dd:DragDrop.IsDropTarget="True"
+                 dd:DragDrop.DropHandler="{Binding CustomDropHandler}" />
+      </Grid>
+    </TabItem>
   </TabControl>
 </Window>
diff --git a/GongSolutions.Wpf.DragDrop/DragDrop.cs b/GongSolutions.Wpf.DragDrop/DragDrop.cs
@@ -332,28 +332,38 @@ private static void IsDropTargetChanged(DependencyObject d, DependencyPropertyCh
 
       if ((bool)e.NewValue == true) {
         uiElement.AllowDrop = true;
-        //uiElement.PreviewDragEnter += DropTarget_PreviewDragEnter;
-        //uiElement.PreviewDragLeave += DropTarget_PreviewDragLeave;
-        //uiElement.PreviewDragOver += DropTarget_PreviewDragOver;
-        //uiElement.PreviewDrop += DropTarget_PreviewDrop;
-
-        uiElement.DragEnter += DropTarget_PreviewDragEnter;
-        uiElement.DragLeave += DropTarget_PreviewDragLeave;
-        uiElement.DragOver += DropTarget_PreviewDragOver;
-        uiElement.Drop += DropTarget_PreviewDrop;
-        uiElement.GiveFeedback += DropTarget_GiveFeedback;
+
+        if (uiElement is ItemsControl) {
+          // use normal events for ItemsControls
+          uiElement.DragEnter += DropTarget_PreviewDragEnter;
+          uiElement.DragLeave += DropTarget_PreviewDragLeave;
+          uiElement.DragOver += DropTarget_PreviewDragOver;
+          uiElement.Drop += DropTarget_PreviewDrop;
+          uiElement.GiveFeedback += DropTarget_GiveFeedback;
+        } else {
+          // issue #85: try using preview events for all other elements than ItemsControls
+          uiElement.PreviewDragEnter += DropTarget_PreviewDragEnter;
+          uiElement.PreviewDragLeave += DropTarget_PreviewDragLeave;
+          uiElement.PreviewDragOver += DropTarget_PreviewDragOver;
+          uiElement.PreviewDrop += DropTarget_PreviewDrop;
+          uiElement.PreviewGiveFeedback += DropTarget_GiveFeedback;
+        }
       } else {
         uiElement.AllowDrop = false;
-        //uiElement.PreviewDragEnter -= DropTarget_PreviewDragEnter;
-        //uiElement.PreviewDragLeave -= DropTarget_PreviewDragLeave;
-        //uiElement.PreviewDragOver -= DropTarget_PreviewDragOver;
-        //uiElement.PreviewDrop -= DropTarget_PreviewDropTest;
-
-        uiElement.DragEnter -= DropTarget_PreviewDragEnter;
-        uiElement.DragLeave -= DropTarget_PreviewDragLeave;
-        uiElement.DragOver -= DropTarget_PreviewDragOver;
-        uiElement.Drop -= DropTarget_PreviewDrop;
-        uiElement.GiveFeedback -= DropTarget_GiveFeedback;
+
+        if (uiElement is ItemsControl) {
+          uiElement.DragEnter -= DropTarget_PreviewDragEnter;
+          uiElement.DragLeave -= DropTarget_PreviewDragLeave;
+          uiElement.DragOver -= DropTarget_PreviewDragOver;
+          uiElement.Drop -= DropTarget_PreviewDrop;
+          uiElement.GiveFeedback -= DropTarget_GiveFeedback;
+        } else {
+          uiElement.PreviewDragEnter -= DropTarget_PreviewDragEnter;
+          uiElement.PreviewDragLeave -= DropTarget_PreviewDragLeave;
+          uiElement.PreviewDragOver -= DropTarget_PreviewDragOver;
+          uiElement.PreviewDrop -= DropTarget_PreviewDrop;
+          uiElement.PreviewGiveFeedback -= DropTarget_GiveFeedback;
+        }
 
         Mouse.OverrideCursor = null;
       }

diff --git a/GongSolutions.Wpf.DragDrop/DropInfo.cs b/GongSolutions.Wpf.DragDrop/DropInfo.cs
@@ -43,9 +43,17 @@ public DropInfo(object sender, DragEventArgs e, DragInfo dragInfo)
       this.VisualTarget = sender as UIElement;
       // if drop target isn't a ItemsControl
       if (!(this.VisualTarget is ItemsControl)) {
-        this.VisualTarget = VisualTreeExtensions.GetVisualAncestor<ItemsControl>(this.VisualTarget) ?? this.VisualTarget;
+        // try to find next ItemsControl
+        var itemsControl = VisualTreeExtensions.GetVisualAncestor<ItemsControl>(this.VisualTarget);
+        if (itemsControl != null) {
+          // now check if this ItemsControl is a drop target
+          if (DragDrop.GetIsDropTarget(itemsControl)) {
+            this.VisualTarget = itemsControl;
+          }
+        }
       }
-      this.DropPosition = e.GetPosition(this.VisualTarget);
+      // visual target can be null, so give us a point...
+      this.DropPosition = this.VisualTarget != null ? e.GetPosition(this.VisualTarget) : new Point();
 
       if (this.VisualTarget is ItemsControl) {
         var itemsControl = (ItemsControl)this.VisualTarget;