Given that you have a control that fires a command:
Is there a way to prevent the command from being fired
If your control derives from System.Windows.Forms.Control, you can use the double click event.
If it doesn't derive from System.Windows.Forms.Control, then wire up mousedown instead and confirm the click count == 2 :
private void Button_MouseDown(object sender, MouseButtonEventArgs e)
{
if (e.ClickCount == 2)
{
//Do stuff
}
}