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Auto Expand on Drag Over

RadTreeView offers you the ability to automatically expand a treeview node when dragging items over the node. In order to do that you need to perform the following action:

  • When dragging items over your treeview, move the mouse cursor over the treeview expander. The result will be an automatically expanded node. WPF RadTreeView Auto Expand on Drag Over

The RadTreeView exposes a property DropExpandDelay, which sets the delay for the expand behavior. The property is of type TimeSpan. Here is a sample code showing you how to set it:

radTreeView.DropExpandDelay = TimeSpan.FromSeconds(5); 
radTreeView.DropExpandDelay = TimeSpan.FromSeconds(5) 

Disable Auto Expand on DragOver

The RadTreeView doesn't actually allow you to disable the auto-expand feature, however you can set the value of the DropExpandDelay property to represent a long period of time. This way your users won't trigger the auto-expand at all while dragging over an item. For instance you can set the DropExpandDelay to an hour:

<telerik:RadTreeView IsDragDropEnabled="True" DropExpandDelay="1:0:0"/> 

You can also set the value from code-behind:

radTreeView.DropExpandDelay = TimeSpan.FromMinutes(60);      
radTreeView.DropExpandDelay = TimeSpan.FromMinutes(60) 

See Also

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