Drag and Drop Treeview Items between 2 Treeviews

Maybe just a brief explanation on how I go about populating the first treeview. What I do is in the code I add TreeViewItems that can be a collection of multiple TreeViewItems. When I am Starting to do the Dragging of a selected TreeViewItem, I make use of the following piece of code:

DragDrop.DoDragDrop(this, TreeView1.SelectedItem, DragDropEffects.Copy | DragDropEffects.Move);

With a DragOver Event on the second treeview I ensure that what is being dragged is a TreeViewItem, but when on the second treeview the mouse Cursor shows that I am unable to drop the dragged Item onto the TreeView control. I also made sure that the AllowDrop = true on the second Treeview.

I have tried the DragLeave on the second treeview but it doesn't seem to fire correctly.

Gerhard

I added a TextBox on the form with the 2 Treeviews and when I drag a treeview item from the first treeview, the Drop event fires for the textbox and the Data object that has been passed is actually the TreeViewItem that is selected in the first Treeview. The Cursor when dragging the TreeViewItem over the Textbox changes to indicate that I can drop the dragged item while on the second treeview the cursor changes to indicate that I am unable to drop the dragged Item.

This brings me to the following question: Is the Drop event been fully implemented on the TreeView control?

Any ideas on how I can get this to work?

Gerhard

Gerhard, let me clarify something about (Rich)TextBox, TreeView and TreeViewItem. RichTextBox and TextBox natively implement drag/drop handlers, so you can move text around out-of-the-box. There are pretty clear semantics about what it means to move text from one such control to another.

TreeView and TreeViewItem are different beasts. Typically they represent something else other than a piece of UI, and especially in Avalon, they are very likely to be data-bound to something else. You would normally want to update the backing data and let your data-bound UI update accordingly, although this is not always the case. The short of it is that TreeViewItem does not have an OOB implementation for drag/drop, and that's what you're seeing.

Implementing drag/drop can be as simple as firing DragDrop, which you're already doing, setting AllowDrop to True, and adding handlers to update the cursor and perform the selected operation. You'll need to extract the item from its parent and reattach it to the new parent in your handler.

I'll be posting a sample on my blog showing how you can drag / drop TreeView items within the next day or so.

Marcelo

The URL is http://blogs.msdn.com/marcelolr/. I'm planning to continue with drag/drop options, and I'll try to steer a future post to cover your scenario.

Good to hear it works for you, but I have one small question about this. How do you get the target item to drop the dragged item on?