Prevent drag and drop outside of the current control (TreeNodes in a TreeView)

Question

I'm maintaining a Windows app that has multiple forms in the one window (form1, form2, form3). I'm treating the other form2 and form3 as black boxes at the moment. In form1 I have a TreeView, and I'm implementing drag and drop functionality within that TreeView. How can I prevent a drop outside of the form1 control? I'm implementing 3 events handlers: private void treeView_ItemDrag (...) { DoDragDrop(e.Item, DragDropEffects.Move); } private void treeView_DragEvent (...) { e.Effect = DragDropEffects.Move; } private void treeView_DragDrop (...) { //the node move logic here } form2 and form3 have a drag and drop relationship between them, so when I drag a node from form1 into form3 by default it allows the move (bad). I want to be able to prevent this from the form1 control code. How can I prevent a drop outside of the form1 control? I've looked at the _DragLeave event, but I'm unsure how to control the operation without the DragEventArgs. JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

There is this little know property in the Cursor object that can restrict the mouse movement only to a certain rectangle. this as a global variable for Form1 Rectangle _originalClip; this goes in your Form1_Load event _originalClip = Cursor.Clip; this could be in your treeView.ItemDrag, forcing the cursor inside the form1 client area Cursor.Clip = form1.RectangleToScreen(form1.ClientRectangle); Now you need to restore the original clip area. A good place will be in the treeView.DragDrop. But to be on the safe side put also in your Form1_Closing event Cursor.Clip = _originalClip;