Invalidates the specified part 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.
public final void invalidate()
public final void invalidate( Rectangle rc )
public final void invalidate( Region region )
rc
A Rectangle object that represents the area to add to the update region.
region
A Region object that represents the area.
Calling this method does not force a synchronous paint; to force a synchronous paint, call the update method after calling the invalidate method. If this method is called with no parameters, the entire client area is added to the update region.