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

Subscribe FormClosing event

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
    e.Cancel = e.CloseReason == CloseReason.UserClosing;
}

Only one line in the method body.