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Nested Drag and Drop

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DragAndDrop
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Frustrated Dev
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Frustrated Dev asked on 02 Apr 2010, 03:01 AM
Please Disregard. I figured it out. I was not casting the destination properly.

Hello,

I have an ItemsControl where each item is a TreeView. Below this ItemsControl is a GridView with a list of items. I'm trying to allow a user to drag items from the GridView into one of the TreeViews in the ItemsControl. When a user drops the item from the GridView onto a TreeView, the item would get added to that specific TreeView.  My XAML looks like the following:

<Grid> 
  <Grid.RowDefinitions> 
    <RowDefinition /> 
    <RowDefinition />  
  </Grid.RowDefinitions> 
 
  <Grid> 
    <Grid.RowDefinitions> 
      <RowDefinition Height="Auto" /> 
      <RowDefinition /> 
    </Grid.RowDefinitions> 
 
    <StackPanel Orientation="Horizontal"
      <TextBlock Text="Tasks" VerticalAlignment="Center" /> 
    </StackPanel> 
 
    <ItemsControl x:Name="myItemsControl" Grid.Row="1"   
      telerikDragDrop:RadDragAndDropManager.AllowDrag="True"   
      Loaded="myItemsControl_Loaded"
      <ItemsControl.ItemTemplate> 
        <DataTemplate> 
          <navigation:RadTreeView x:Name="myTree" HorizontalAlignment="Stretch" HorizontalContentAlignment="Stretch" Loaded="myTree_Loaded"
            <navigation:RadTreeViewItem Header="{Binding}"
              <navigation:RadTreeViewItem.ItemTemplate> 
                <DataTemplate> 
                  <TextBlock Text="{Binding}" /> 
                </DataTemplate> 
              </navigation:RadTreeViewItem.ItemTemplate> 
            </navigation:RadTreeViewItem> 
          </navigation:RadTreeView> 
        </DataTemplate> 
      </ItemsControl.ItemTemplate> 
    </ItemsControl> 
  </Grid> 
 
  <Grid Grid.Row="1"
    <Grid.RowDefinitions> 
      <RowDefinition Height="Auto" /> 
      <RowDefinition /> 
    </Grid.RowDefinitions> 
 
    <StackPanel Orientation="Horizontal"
      <TextBlock Text="Days" /> 
    </StackPanel> 
 
    <telerik:RadGridView x:Name="myGridView" UseAlternateRowStyle="True"  
      AutoGenerateColumns="False" ShowGroupPanel="False" Grid.Row="1"  
      telerikDragDrop:RadDragAndDropManager.AllowDrop="True"  
      Loaded="myGridView_Loaded"
      <telerik:RadGridView.RowStyle> 
        <Style TargetType="gridview:GridViewRow"
          <Setter Property="telerikDragDrop:RadDragAndDropManager.AllowDrag" Value="True" /> 
        </Style> 
       </telerik:RadGridView.RowStyle> 
     <telerik:RadGridView.Columns> 
     <telerik:GridViewDataColumn Header="Day" DataMemberBinding="{Binding}" IsReadOnly="True" IsFilterable="False" IsGroupable="False"  /> 
   </telerik:RadGridView.Columns> 
 </telerik:RadGridView> 
 </Grid> 
 </Grid> 
 


I can drag items from the GridView. But I cannot identify how to drop it on one of the TreeViews in the ItemsControl.  I have a message box that should say "dropped". But it is not triggering. I'm not sure what I'm doing wrong. My C# code is provided below. What am I doing wrong? How can I accomplish this?

Thank you for your help,

private void myTree_Loaded(object sender, RoutedEventArgs e) 
  RadTreeView myTreeView = (RadTreeView)(sender); 
  RadDragAndDropManager.SetAllowDrop(myTreeView, true); 
 
  RadDragAndDropManager.AddDropQueryHandler(myTreeView, myTreeView_OnDropQuery); 
  RadDragAndDropManager.AddDropInfoHandler(myTreeView, myTreeView_OnDropInfo); 
 
private void myTreeView_OnDropQuery(object sender, Telerik.Windows.Controls.DragDrop.DragDropQueryEventArgs e) 
  RadGridView destination = sender as RadGridView; 
  if (destination != null
  { 
    e.Handled = true
    e.QueryResult = true
  } 
 
private void myTreeView_OnDropInfo(object sender, Telerik.Windows.Controls.DragDrop.DragDropEventArgs e) 
  RadGridView destination = sender as RadGridView; 
  if (e.Options.Status == Telerik.Windows.Controls.DragDrop.DragStatus.DropComplete) 
  { 
    MessageBox.Show("dropped!"); 
  } 
 
private void myItemsControl_Loaded(object sender, RoutedEventArgs e) 
  List<string> tasks = new List<string>(); 
  tasks.Add("Sweep Floor"); 
  tasks.Add("Task out Garbage"); 
  tasks.Add("Clean Windows"); 
   
  myItemsControl.ItemsSource = tasks; 
 
private void myGridView_Loaded(object sender, RoutedEventArgs e) 
  RadDragAndDropManager.AddDropQueryHandler(myGridView, myGridView_OnDropQuery); 
  RadDragAndDropManager.AddDropInfoHandler(myGridView, myGridView_OnDropInfo); 
  RadDragAndDropManager.AddDragQueryHandler(myGridView, myGridView_OnDragQuery); 
  RadDragAndDropManager.AddDragInfoHandler(myGridView, myGridView_OnDragInfo); 
 
  List<string> days = new List<string>(); 
  days.Add("Sunday"); 
  days.Add("Monday"); 
  days.Add("Tuesday"); 
  days.Add("Wednesday"); 
  days.Add("Thursday"); 
  days.Add("Friday"); 
  days.Add("Saturday"); 
  myGridView.ItemsSource = days; 
 
private void myGridView_OnDragQuery(object sender, DragDropQueryEventArgs e) 
  RadGridView gridView = sender as RadGridView; 
  if (gridView != null
    e.Options.Payload = gridView.SelectedItem; 
 
   // Inform the event handlers that we have programmatically handled it 
   e.QueryResult = true
   e.Handled = true
 
private void myGridView_OnDragInfo(object sender, DragDropEventArgs e) 
  RadGridView gridView = sender as RadGridView; 
  string draggedItem = e.Options.Payload as string
 
  if (e.Options.Status == DragStatus.DragInProgress) 
  { 
    //Setting up a drag cue: 
    ContentControl cue = new ContentControl(); 
    //Choosing a template for the items: 
    cue.ContentTemplate = this.Resources["MyTemplate"as DataTemplate; 
    cue.Content = draggedItem; 
    e.Options.DragCue = cue; 
  } 
  else if (e.Options.Status == DragStatus.DragComplete) 
  { 
    //deleting the dragged item from the RadGridView 
    //                IList source = gridView.ItemsSource as IList; 
    //                source.Remove(draggedItem); 
  } 
 
private void myGridView_OnDropQuery(object sender, Telerik.Windows.Controls.DragDrop.DragDropQueryEventArgs e) 
  RadGridView destination = sender as RadGridView; 
  if (destination != null
  { 
    e.Handled = true
    e.QueryResult = true
  } 
 
private void myGridView_OnDropInfo(object sender, Telerik.Windows.Controls.DragDrop.DragDropEventArgs e) 
  RadGridView destination = sender as RadGridView; 
  if (e.Options.Status == Telerik.Windows.Controls.DragDrop.DragStatus.DropComplete) 
   { 
   } 

1 Answer, 1 is accepted

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Tina Stancheva
Telerik team
answered on 02 Apr 2010, 03:36 PM
Hello Frustrated Dev,

We are glad to hear that.

Please let us know if you need more info.

All the best,
Tina Stancheva
the Telerik team

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DragAndDrop
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Frustrated Dev
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Tina Stancheva
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