How to Disable Alt + F4 closing form?

Question

What is the best way to disable Alt + F4 in a c# win form to prevent the user from closing the form?

I am using a form as a popup dialog to dis

Answer 1

I am using a form as a popup dialog to display a progress bar and I do not want the user to be able to close it.

If the user is determined to close your app (and knowledgeable) enough to press alt+f4, they'll most likely also be knowledgeable enough to run task manager and kill your application instead.

At least with alt+f4 your app can do a graceful shutdown, rather than just making people kill it. From experience, people killing your app means corrupt config files, broken databases, half-finished tasks that you can't resume, and many other painful things.

At least prompt them with 'are you sure' rather than flat out preventing it.