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

<p>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.</p>

You could handle the
```
FormClosing
```
event and set
```
FormClosingEventArgs.Cancel
```
to
```
true
```
.