Can someone explain the difference between the Graphics
object that is passed as pevent.Graphics
and the one that is returned by a call to this.C
Whenever a Paint
event is raised, you are given a Graphics
object to draw into. This is passed as pevent.Graphics
. Drawing into this Graphics
object is how you paint the element.
CreateGraphics
should basically never be used. It creates a new Graphics
object on-the-fly from a window handle. You can draw into the Graphics
object it returns, but anything you draw into it will be obliterated the next time that a Paint
event is raised.
The only time you might want to use CreateGraphics
is for special effects, like showing real-time feedback during a drag. You want that to be erased the next time that the element is repainted, so you go ahead and use CreateGraphics
to get a temporary canvas to draw onto while the drag event is in progress.
You will never use CreateGraphics
inside of a Paint
event handler method. There is no point—you are given a Graphics
object to draw into already!