Press Escape key to call method

问题:

Is there a way to start a method in C# if a key is pressed? For example, Esc?

回答1:

I am writing WinForms application. User fills the textbox and if he wants to delete everything, he just clicks esc key on keyboard

I think you need to handle the KeyDown event.

回答2:

use the OnKeyPress Event of your textbox and in the event

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

回答3:

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;
    }
}

回答4:

You have to switch the form property "KeyPreview" to true or your events will not be fired. Handling these events alone will not do anything even though the events are correct. It will look to you like nothing really happens even though you have subscribed the proper event handlers.

回答5:

First in Properties do > KeyPreview : True

Then :

private void Form1_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.Escape)
        {
            //call your method here
        }
    }

回答6:

In case someone was looking for how to do it in a console application

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

回答7:

Are you writing a Console application, a WinForms application or something else? Are you trying to capture the ESC key at all times (regardless of the focused window/application) or something else?

More context required.

If you're writing a Console app, then you should start looking at things like Console.ReadKey...

^{http://msdn.microsoft.com/en-us/library/system.console.readkey.aspx}

回答8:

With Event KeyPress...

   //Escape 
   if (e.KeyChar == '')
   {
            this.DialogResult = DialogResult.Cancel;
            e.Handled = true;
   }

回答9:

You can use KeyUp event too. I prefer it though.

private void Window_KeyUp(object sender, System.Windows.Input.KeyEventArgs e) {
     if (e.Key == Key.Escape) {
         //WHAT WILL HAPPEN INSERT HERE
     }
}