Change drop target on drop end event

[Roman Gomolko]

I have challenge with TreeView and drag and drop feature.

My goal is to implement next behavior:
1. User drop one item onto another
2. System show pop-up like "Enter node title"
3. Create sub-node to drop target with entered title
4. Append dropped element to created sub-node,

What I'm trying to do

//HierarchyTree.ItemSource = collection of ItemContainer;

HierarchyTree.DragEnded += HierarchyTree_DragEnded;

void HierarchyTree_DragEnded(object sender, RadTreeViewDragEndedEventArgs e) {
            if (e.IsCanceled == true) {
                return;
            }

            RadTreeViewItem item = e.TargetDropItem;
            ItemContainer container = item.Item as ItemContainer;
            if (container != null) {
                if (e.DropPosition == DropPosition.Inside) {
                    Question question = new Question("Condition");
                    ItemContainer newContainer = new ItemContainer(question);
                    newContainer.IsCondition = true;
                    newContainer.Children.Add(container);
                    e.DraggedItems.Clear();
                    e.DraggedItems.Add(newContainer);
                }
            }
        }

Probably it doesn't have any sense. I hope you can provide me with some directions or partial solution.

Best Regards, Roman

[Kiril Stanoev]

Hi Roman,

I have prepared and attached a sample project demonstrating this functionality. The code is pretty self explanatory, but if you have additional questions, let me know.

Kind regards,
Kiril Stanoev
the Telerik team

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[Moises Casusol]

Hi,
   this is what im looking for, but when i tested the example there is an error or bug i guess. After i drag a first item like "John" with a new header, i drag a second name and try to add this before o after "Jhon" but when i drop it the name is not added to the treeview and it was removed from the list. Im using silverlight 3.0 with RadTreeView Q3 2009.

Best Regards
-Lois

[Kiril Stanoev]

Hello Moises,

If you take a look at the OnDropInfo event handler, you will see the following if clause:

if (e.Options.Status == DragStatus.DropComplete && destination is RadTreeView)
{
}

Simply remove destination is RadTreeView and everything should be fine. However, if you still want to make sure you are dropping on the TreeView, extend the if clause so it becomes something like:

if (e.Options.Status == DragStatus.DropComplete && (destination is RadTreeView || destination is RadTreeViewItem))
{
}

Let me know how this works for you.

Best wishes,
Kiril Stanoev
the Telerik team

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[James]

Bug? you cannot drop an item into an existing item - which is EMPTY - i.e, has no triangle to expand.

Repro steps:
- drag "John" to the left
   - in the popup window, give a name to the folder that will sit on the ROOT (only)  - ex. "Folder1"
- now expand "Folder1", you will see the "John" node
- NOW
   - try to drag more items INTO "Folder1" --> you will not see the item
   - try to drag an item to sit UNDER "john" --> item will not get added

I'm still waiting for telerik response on this behaviour - as I've noticed that when working on our application.
Anyone else notice that? any suggestions? 

[Vladislav]

Hi James,

In order to achieve the desired behavior, you should change the example project.
In particular you should replace

treeView1.Items.Add(treeViewItem);

in private void OnDropInfo(object sender, DragDropEventArgs e)
with this snippet:

if ((destination as RadTreeView) != null)
{
    (destination as RadTreeView).Items.Add(treeViewItem);
}
else if ((destination as RadTreeViewItem) != null)
{
    (destination as RadTreeViewItem).Items.Add(treeViewItem);
}

Modifying the example in this way will allow you to drop the dragged item anywhere in the treeview.

Please let us know if this solution works for you.

Kind regards,
Vladislav
the Telerik team

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