Override of Graphics.DrawLine

Question

I seek to @override the DrawLine method of the Graphics class, but I am unsure if this is possible?

I seek to put a validation in

Answer 1

It is not possible for normal code to replace method that is not designed to be replaced/overriden.

You can

• pre-process (i.e. ILDASM/modify/ILASM) all calling assemblies to use your new method
• replace System.Drawing assembly with your own
• use some existing framework that allows to override such methods like Moles or Fakes if you need it for unit testing.

Answer 2

You just need a separate method. Put it wherever you want:

void CheckedDrawLine(Graphics g, int x1, int y1, int x2, int y2, int stopY) {
    // Do the validation, draw the line
}

And you could make it into an extension method by sticking it in a static class:

void CheckedDrawLine(this Graphics g, int x1, int y1, int x2, int y2, int stopY) {
    // Do the validation, draw the line
}

to do a g.CheckedDrawLine(...) instead of a CheckedDrawLine(g, ...).