I would like to add my own button to the form and pass a delegate (with its own functionality) to the method, which would be called when this new button was pressed.

Tell me where to start?

    1 answer 1

    MessageBox is essentially just a static class that accesses WinAPI and is not even a control. Therefore, to expand it, alas, will not work. If you want to have a custom message box, you will have to write your own or look for ready-made implementations on the Internet.