Question

I want to drag data from a ListView and drop it in a TreeView(the draging works fine). I use DataBinding and ItemTemplate to fill the TreeView.

<TreeView ItemsSource='{Binding Groups}' Name='tvGroups' AllowDrop='True'           Drop='tvDrop' DragOver='tvDragOver'>     <TreeView.ItemTemplate>         <HierarchicalDataTemplate ItemsSource='{Binding Participants}'>             <StackPanel Orientation='Horizontal'>                 <TextBlock Text='{Binding Name}' />                 <Button Tag='{Binding .}' Click='Button_Click_2'>                     <Image Source='Resources/cross.png' />                 </Button>             </StackPanel>             <HierarchicalDataTemplate.ItemTemplate>                 <DataTemplate>                     <StackPanel Orientation='Horizontal' >                         <TextBlock Text='{Binding Alias}' />                         <Button Tag='{Binding .}' Name='btnDeleteParticipants' Click='btnParticipants_Click' >                             <Image Source='Resources/cross.png' />                         </Button>                     </StackPanel>                 </DataTemplate>             </HierarchicalDataTemplate.ItemTemplate>         </HierarchicalDataTemplate>     </TreeView.ItemTemplate> </TreeView> 

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private void tvDrop(object sender, DragEventArgs e) {     if (e.Effects == DragDropEffects.Copy &&         e.Data.GetDataPresent(typeof(Participant)))     {         Participant data = e.Data.GetData(typeof(Participant)) as Participant;     } } 

A Participant is dragged from the ListView to the TreeView. Now I need to find the Group. Any ideas where to get the right Group from the TreeView?

Answer 1

I would simply set the Drop=’tvDrop’ and DragOver=’tvDragOver’ on the StackPanel in the HierarchicalDataTemplate’s ItemTemplate.

This way 1) You don’t have any risk of getting an event when something is dropped out of a group 2) You can safely cast the Sender to a FrameworkElement and get the DataContext and cast it to your class.

You can also set a different handler on the treeview itself if you need to support dragging out of the groups.