Press Escape key to call method

In case someone is looking for how to do this in a console application

if (Console.ReadKey().Key == ConsoleKey.Escape)
{
    return;
}

As others have mentioned, handle the KeyDown or KeyUp event of the appropriate control. The KeyPress event would work for the Escape key as well, though it will not trigger for some keys, such as Shift, Ctrl or ALt.

If you want to execute this function anytime the user presses the Escape key, then you probably want to handle the event on the Form. If you do this, you will probably also want to set the Form's KeyPreview property to true. This will allow the Form control to receive the event even if the focus is currently inside of one of the child controls.

If you want the behavior to be specific to a control, such as clearing the text within a textbox that currently has focus, then you should handle the KeyDown or KeyUp event of the TextBox control. This way, your event handler will not be triggered if the user presses the escape key outside of the textbox.

In some situations you might want to prevent child controls from handling the same event that you've just handled. You can use the SuppressKeyPress property on the KeyEventArgs class to control this behavior:

private void Form1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Escape)
    {
        MessageBox.Show("Escape key pressed");

        // prevent child controls from handling this event as well
        e.SuppressKeyPress = true;
    }
}

use the OnKeyPress Event of your textbox and in the event

if(e.KeyCode==Keys.Escape)
{
    yourTextBox.Text = string.Empty;
}