void panel_MouseDown(object sender, MouseEventArgs e) { if (sender.GetType() == typeof(SmallButtonControl)) { SmallButtonControl btnSamll = sender as SmallButtonControl; PanelControl panel = btnSamll.Parent as PanelControl; panel.DoDragDrop(panel, DragDropEffects.Move); } else if (sender.GetType() == typeof(LargeButtonControl)) { LargeButtonControl btnLarge = sender as LargeButtonControl; PanelControl panel = btnLarge.Parent as PanelControl; panel.DoDragDrop(panel, DragDropEffects.Move); } }