wrong source&destination items with TreeView in UI for Silverlight

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wrong source&destination items with TreeView

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DragAndDrop

This is a migrated thread and some comments may be shown as answers.

Adrien asked on 18 May 2009, 11:38 AM

I want to drag & drop between two treeviews, but I rarely have the items I want. Often the source (e.Options.Source) is the root item of my treeview or sometimes the parent item of the item wanted. The same thing happens for the destination on drop.

Do you know what might cause the problem ?

Here is an example to reproduce the problem, with a visualization of the source item while dragging. When dragging

Page.xaml

    
            <UserControl x:Class="SilverlightApplication1.Page"  
        
                xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"   
        
                xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
        
                xmlns:telerikNavigation="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Navigation"  
        
                xmlns:telerikDragDrop="clr-namespace:Telerik.Windows.Controls.DragDrop;assembly=Telerik.Windows.Controls" 
        
                Width="600" Height="400"> 
        
                <Grid x:Name="LayoutRoot" Background="White"> 
        
                    <StackPanel Orientation="Horizontal"> 
        
                        <telerikNavigation:RadTreeView x:Name="xTreeView" IsEditable="True"> 
        
                            <telerikNavigation:RadTreeView.ItemContainerStyle> 
        
                                <Style TargetType="telerikNavigation:RadTreeViewItem"> 
        
                                    <Setter Property="telerikDragDrop:RadDragAndDropManager.AllowDrag" Value="True" /> 
        
                                    <Setter Property="telerikDragDrop:RadDragAndDropManager.AllowDrop" Value="True" /> 
        
                                    <Setter Property="IsExpanded" Value="True" /> 
        
                                </Style> 
        
                            </telerikNavigation:RadTreeView.ItemContainerStyle> 
        
                            <telerikNavigation:RadTreeViewItem Header="Root"> 
        
                                <telerikNavigation:RadTreeViewItem Header="Folder"> 
        
                                    <telerikNavigation:RadTreeViewItem Header="File" /> 
        
                                    <telerikNavigation:RadTreeViewItem Header="File" /> 
        
                                </telerikNavigation:RadTreeViewItem> 
        
                            </telerikNavigation:RadTreeViewItem> 
        
                        </telerikNavigation:RadTreeView> 
        
                    </StackPanel> 
        
                </Grid> 
        
            </UserControl>

Page.xaml.cs

    
            using System; 
        
            using System.Windows; 
        
            using System.Windows.Controls; 
        
            using System.Windows.Media; 
        
            using Telerik.Windows; 
        
            using Telerik.Windows.Controls; 
        
            using Telerik.Windows.Controls.DragDrop; 
        
            namespace SilverlightApplication1 
        
            { 
        
                public partial class Page : UserControl 
        
                { 
        
                    public Page() 
        
                    { 
        
                        InitializeComponent(); 
        
                        xTreeView.AddHandler(RadDragAndDropManager.DragQueryEvent, new EventHandler<DragDropQueryEventArgs>(OnTreeDragQuery), false); 
        
                    } 
        
                    private void OnTreeDragQuery(object sender, DragDropQueryEventArgs e) 
        
                    { 
        
                        RadTreeViewItem vControlItem = e.Options.Source as RadTreeViewItem; 
        
                        if (e.Options.Status == DragStatus.DragQuery) 
        
                        { 
        
                            if (vControlItem != null) 
        
                            { 
        
                                e.Options.ArrowCue = RadDragAndDropManager.GenerateArrowCue(); 
        
                                TextBlock vPreview = new TextBlock(); 
        
                                vPreview.Text = vControlItem.Header.ToString(); 
        
                                vPreview.Foreground = new SolidColorBrush(Colors.Blue); 
        
                                vPreview.FontWeight = FontWeights.Bold; 
        
                                vPreview.Opacity = 0.6; 
        
                                e.Options.Payload = vControlItem; 
        
                                e.Options.DragCue = vPreview; 
        
                                e.QueryResult = true; 
        
                                e.Handled = true; 
        
                            } 
        
                            else 
        
                            { 
        
                                e.QueryResult = false; 
        
                                e.Handled = false; 
        
                            } 
        
                        } 
        
                    } 
        
                } 
        
            }

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