Invalidates the specified region of the control (adds it to the control's update region, which is the area that will be repainted at the next paint operation), and causes a paint message to be sent to the control.
- rc
- A System.Drawing.Rectangle that represents the region to invalidate.
Calling the Control.Invalidate(System.Drawing.Region) method does not force a synchronous paint; to force a synchronous paint, call the Control.Update method after calling the Control.Invalidate(System.Drawing.Region) method. When this method is called with no parameters, the entire client area is added to the update region.