System.Windows.Forms.Control.GetContainerControl C# (CSharp) Method

		public IContainerControl GetContainerControl() {
			Control	current = this;

			while (current!=null) {
				if ((current is IContainerControl) && ((current.control_style & ControlStyles.ContainerControl)!=0)) {
					return (IContainerControl)current;
				}
				current = current.parent;
			}
			return null;
		}

 internal void FocusActiveControlInternal()
 {
     if (active_control != null && active_control.Visible)
     {
         // Avoid focus loops, especially with ComboBoxes, on Win98/ME.
         IntPtr focusHandle = XplatUI.GetFocus();
         if (focusHandle == IntPtr.Zero || Control.FromChildHandle(focusHandle) != active_control)
         {
             XplatUI.SetFocus(active_control.Handle);
         }
     }
     else
     {
         // Determine and focus closest visible parent
         ContainerControl cc = this;
         while (cc != null && !cc.Visible)
         {
             Control parent = cc.Parent;
             if (parent != null)
             {
                 cc = parent.GetContainerControl() as ContainerControl;
             }
             else
             {
                 break;
             }
         }
         if (cc != null && cc.Visible)
         {
             XplatUI.SetFocus(cc.Handle);
         }
     }
 }