Docking Drag & Drop Events

Docking Drag & Drop Events

Drag & Drop Events:

• DoDragDropEnd
• DoDragDropQuit

Event Firing
At the end of a page drag and drop action within the docking system one of these events will be fired. If the drop occurred with success then the DoDragDropEnd event will be fired to indicate success. If the drag operation was cancelled for any reason then the DoDragDropQuit event will be fired instead. Note that only one of these events is fired at the end of an operation and never both.

External Event Usage
The most likely scenario for needing these events is if you are starting off a drag and drop operation manually from outside the docking system and then need to know when the operation has been completed. For example, you might have a TreeView that contains a set of nodes. When the user starts dragging one of these tree nodes you want to create a floating window as part of the docking system and allow that floating window to be dragged just like any other docking content. The creation of a new docking page and associated floating window is very simple and shown in example code below. Once the floating window is created you would call the docking manager DoDragDrop method in order to request that a drag operation occur with the newly created floating window. You will need to know when this drag operation completes so you can update the status of your TreeView control. By hooking both the DoDragDropEnd and DoDragDropQuit you can update as needed when the operation completes. The following sample code shows how this might look in practice.

protected override void OnMouseMove(MouseEventArgs e)  
{  
   Point pt = new Point(e.X, e.Y);

   // Has a node been selected from dragging?  
   if (_dragNode != null)  
   {

      // Create a new page for the docking system  
      KryptonPage dp =  new KryptonPage("New Page");

      // Create a floating window that contains the new page  
      KryptonDockingFloatingWindow fw =
kryptonDockingManager.AddFloatingWindow("Floating", new KryptonPage[] { dp });

      // Spin message loop so new window appears  
      Application.DoEvents();

      // We want to know when the drag drop operating is finished  
      kryptonDockingManager.DoDragDropEnd += new
EventHandler(kryptonDockingManager_DoDragDropFinished);  
      kryptonDockingManager.DoDragDropQuit += new
EventHandler(kryptonDockingManager_DoDragDropFinished);

      // Drag the new floating window around  
      kryptonDockingManager.DoDragDrop(MousePosition, pt, dp, fw);  
   }

   base.OnMouseMove(e);

}

 

private void kryptonDockingManager_DoDragDropFinished(object sender, EventArgs e)  
{

   // Remember to unhook from no longer needed events  
   kryptonDockingManager.DoDragDropEnd -= new EventHandler(kryptonDockingManager_DoDragDropFinished);  
   kryptonDockingManager.DoDragDropQuit -= new EventHandler(kryptonDockingManager_DoDragDropFinished);

   // Drag has finished so set drag node back to null  
   _dragNode = null;  
}