add UnfilteredInsertIndex to DropInfo

Gets the current insert position within the source (unfiltered). This should be only used in a Drop action. This works only correct with different objects (string, int, etc won't work correct).
punker76 · Jan 16, 2015 · 51933a6 · 51933a6
1 parent 6c8f5f9
commit 51933a6
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Showing 4 changed files with 64 additions and 19 deletions.
diff --git a/GongSolutions.Wpf.DragDrop/DefaultDropHandler.cs b/GongSolutions.Wpf.DragDrop/DefaultDropHandler.cs
@@ -1,12 +1,10 @@
-using System;
-using System.Collections;
+using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 using System.Windows;
 using GongSolutions.Wpf.DragDrop.Utilities;
 using System.Windows.Controls;
-using System.ComponentModel;
 
 namespace GongSolutions.Wpf.DragDrop
 {
@@ -22,20 +20,20 @@ public virtual void DragOver(IDropInfo dropInfo)
 
     public virtual void Drop(IDropInfo dropInfo)
     {
-      var insertIndex = dropInfo.InsertIndex;
-      var destinationList = GetList(dropInfo.TargetCollection);
+      var insertIndex = dropInfo.InsertIndex != dropInfo.UnfilteredInsertIndex ? dropInfo.UnfilteredInsertIndex : dropInfo.InsertIndex;
+      var destinationList = dropInfo.TargetCollection.ToList();
       var data = ExtractData(dropInfo.Data);
 
       if (dropInfo.DragInfo.VisualSource == dropInfo.VisualTarget) {
-        var sourceList = GetList(dropInfo.DragInfo.SourceCollection);
+        var sourceList = dropInfo.DragInfo.SourceCollection.ToList();
 
         foreach (var o in data) {
           var index = sourceList.IndexOf(o);
 
           if (index != -1) {
             sourceList.RemoveAt(index);
 
-            if (sourceList == destinationList && index < insertIndex) {
+            if (Equals(sourceList, destinationList) && index < insertIndex) {
               --insertIndex;
             }
           }
@@ -59,7 +57,7 @@ public static bool CanAcceptData(IDropInfo dropInfo)
       }
 
       if (dropInfo.DragInfo.SourceCollection == dropInfo.TargetCollection) {
-        return GetList(dropInfo.TargetCollection) != null;
+        return dropInfo.TargetCollection.ToList() != null;
       } else if (dropInfo.DragInfo.SourceCollection is ItemCollection) {
         return false;
       } else if (dropInfo.TargetCollection == null) {
@@ -82,15 +80,6 @@ public static IEnumerable ExtractData(object data)
       }
     }
 
-    public static IList GetList(IEnumerable enumerable)
-    {
-      if (enumerable is ICollectionView) {
-        return ((ICollectionView)enumerable).SourceCollection as IList;
-      } else {
-        return enumerable as IList;
-      }
-    }
-
     protected static bool IsChildOf(UIElement targetItem, UIElement sourceItem)
     {
       var parent = ItemsControl.ItemsControlFromItemContainer(targetItem);

diff --git a/GongSolutions.Wpf.DragDrop/DropInfo.cs b/GongSolutions.Wpf.DragDrop/DropInfo.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections;
+using System.Linq;
 using System.Windows;
 using System.Windows.Controls;
 using GongSolutions.Wpf.DragDrop.Utilities;
@@ -18,6 +19,9 @@ namespace GongSolutions.Wpf.DragDrop
   /// </remarks>
   public class DropInfo : IDropInfo
   {
+    private ItemsControl itemParent = null;
+    private UIElement item = null;
+
     /// <summary>
     /// Initializes a new instance of the DropInfo class.
     /// </summary>
@@ -57,7 +61,7 @@ public DropInfo(object sender, DragEventArgs e, DragInfo dragInfo)
 
       if (this.VisualTarget is ItemsControl) {
         var itemsControl = (ItemsControl)this.VisualTarget;
-        var item = itemsControl.GetItemContainerAt(this.DropPosition);
+        item = itemsControl.GetItemContainerAt(this.DropPosition);
         var directlyOverItem = item != null;
 
         this.TargetGroup = itemsControl.FindGroup(this.DropPosition);
@@ -70,7 +74,7 @@ public DropInfo(object sender, DragEventArgs e, DragInfo dragInfo)
         }
 
         if (item != null) {
-          var itemParent = ItemsControl.ItemsControlFromItemContainer(item);
+          itemParent = ItemsControl.ItemsControlFromItemContainer(item);
 
           this.InsertIndex = itemParent.ItemContainerGenerator.IndexFromContainer(item);
           this.TargetCollection = itemParent.ItemsSource ?? itemParent.Items;
@@ -170,6 +174,33 @@ public DropInfo(object sender, DragEventArgs e, DragInfo dragInfo)
     /// </summary>
     public int InsertIndex { get; private set; }
 
+    /// <summary>
+    /// Gets the current insert position within the source (unfiltered) <see cref="TargetCollection"/>.
+    /// </summary>
+    /// <remarks>
+    /// This should be only used in a Drop action.
+    /// This works only correct with different objects (string, int, etc won't work correct).
+    /// </remarks>
+    public int UnfilteredInsertIndex
+    {
+      get
+      {
+        var insertIndex = this.InsertIndex;
+        if (itemParent != null) {
+          var itemSourceAsList = itemParent.ItemsSource.ToList();
+          if (itemSourceAsList != null && itemParent.Items != null && itemParent.Items.Count != itemSourceAsList.Count) {
+            if (insertIndex >= 0 && insertIndex < itemParent.Items.Count) {
+              var indexOf = itemSourceAsList.IndexOf(itemParent.Items[insertIndex]);
+              if (indexOf >= 0) {
+                return indexOf;
+              }
+            }
+          }
+        }
+        return insertIndex;
+      }
+    }
+
     /// <summary>
     /// Gets the collection that the target ItemsControl is bound to.
     /// </summary>

diff --git a/GongSolutions.Wpf.DragDrop/IDropInfo.cs b/GongSolutions.Wpf.DragDrop/IDropInfo.cs
@@ -56,6 +56,15 @@ public interface IDropInfo
     /// </summary>
     int InsertIndex { get; }
 
+    /// <summary>
+    /// Gets the current insert position within the source (unfiltered) <see cref="TargetCollection"/>.
+    /// </summary>
+    /// <remarks>
+    /// This should be only used in a Drop action.
+    /// This works only correct with different objects (string, int, etc won't work correct).
+    /// </remarks>
+    int UnfilteredInsertIndex { get; }
+
     /// <summary>
     /// Gets the collection that the target ItemsControl is bound to.
     /// </summary>

diff --git a/GongSolutions.Wpf.DragDrop/Utilities/TypeUtilities.cs b/GongSolutions.Wpf.DragDrop/Utilities/TypeUtilities.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using System.Collections;
 
@@ -74,5 +75,20 @@ public static Type GetCommonBaseClass(Type[] types)
 
       return ret;
     }
+
+    /// <summary>
+    /// Gets the enumerable as list.
+    /// If enumerable is an ICollectionView then it returns the SourceCollection as list.
+    /// </summary>
+    /// <param name="enumerable">The enumerable.</param>
+    /// <returns>Returns a list.</returns>
+    public static IList ToList(this IEnumerable enumerable)
+    {
+      if (enumerable is ICollectionView) {
+        return ((ICollectionView)enumerable).SourceCollection as IList;
+      } else {
+        return enumerable as IList;
+      }
+    }
   }
 }