Restrict adding control on Panel

Question

How can i restrict adding controls in Panel in C# window controls? I have to restrict user to add controls in a panel at design time.

Answer 1

Set AllowDrop to false.

Answer 2

If you want to limit the types of controls or number of controls one can add to the panel you can make your own subclass of the panel and check the Control type or Control count in an overload of the Controls.Add method.

Edit: Overloading the Controls.Add method was not as easy as I thought, but you can make a new class that extends the Panel class and override the OnControlAdded method to check the type of control that was added. Something like this should work:

class MyPanel : Panel
{

 public MyPanel()
 { }

 protected override void OnControlAdded(ControlEventArgs e)
 {
  base.OnControlAdded(e);

  if (!(e.Control is Label))
  {
   MessageBox.Show("control " + e.Control.Name + " is not a label but a " + e.Control.GetType().ToString());
   Controls.Remove(e.Control);
  }

 }

}