How to trap or hook the key alt f4

Question

1.22/5 (2 votes)

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Hi,

I just want to ask if anyone can provide me with the code on how to trap or hook the key alt f4?

I only need a simple example.
Based from what I see on some threads, they tend to provide complicated code, and I'm just new in c#.
Basically I just want to know the simplest way to trap the key alt f4 and hope someone can provide me with it.

Thanks

Posted 23-Mar-11 22:10pm

Madzmar25

Updated 26-Mar-18 20:51pm

Dalek Dave

v2

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Comments

Sergey Alexandrovich Kryukov 24-Mar-11 4:17am

Tag the question properly especially if you need any more information. WPF? WinForms? ASP.NET?
Next time, tag accurately from the very beginning.
--SA

Dalek Dave 24-Mar-11 9:53am

Edited for Grammar and Readability.

Madzmar25 26-Mar-11 0:11am

Thanks for the help guys... i tried your sample using e.cancel= true and it works... thanks again

3 solutions

Solution 3

VB

Private Sub Frm_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyDown
        'nashe ba ALT+F4 forme karnamaro bebandim

        If e.Alt AndAlso e.KeyCode = Keys.F4 Then
            e.Handled = True
        End If

        'end
    End Sub

in c#

C#

if (e.Alt && e.KeyCode == Keys.F4)
                   {

               e.Handled = true ;

                   }

Posted 7-Jul-12 20:59pm

Mina Mansouri

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Toli Cuturicu · Accepted Answer · 2011-03-24T03:07:00

Solution 2

It may be useful to tell us what you want to achieve...
If you just want to prevent the user from closing the Form / Application by using Alt+F4, you may set e.Cancel = true; in your FormClosing event.

Posted 24-Mar-11 3:07am

Toli Cuturicu

Updated 24-Mar-11 3:08am

v2

Comments

Dalek Dave 24-Mar-11 9:53am

Good Answer.

Sergey Alexandrovich Kryukov 24-Mar-11 12:39pm

Good point, my 5. I'll edit my Answer to reference your advice. Maybe handling the key press is not needed at all.
--SA

Sergey Alexandrovich Kryukov 24-Mar-11 12:46pm

I updated my Answer, added info on both WinForms and WPF.
Thank you very much.
--SA

Sergey Alexandrovich Kryukov · Accepted Answer · 2011-03-23T22:16:00

Solution 1

No traps, not hooks. You need to handle System.Windows.Forms.Control.KeyDown for System.Windows.Forms, or System.Windows.FrameworkElement.KeyDown, System.Windows.FrameworkElement.PreviewKeyDown for WPF. See help on these classes and events.

[EDIT]

Maybe, handling of a keyboard event is not needed at all. As Toli noticed (please see his Answer), this is closing the a form or WPF window, so you need to handle System.Windows.Forms.Form.FormClosing (with opportunity to close the form) or System.Windows.Forms.Form.FormClosed. For WPF, see analogous System.Windows.Window.Closing and System.Windows.Window.Close events.

—SA

Posted 23-Mar-11 22:16pm

Sergey Alexandrovich Kryukov

Updated 24-Mar-11 6:46am

v2

Comments

Sergey Alexandrovich Kryukov 24-Mar-11 4:19am

Tag the Question properly, then ask if you still have questions.
(Please, DO NOT POST AS Answer -- very common annoying mistake, in this case the post will be deleted.)
--SA

Madzmar25 24-Mar-11 4:51am

CAN YOU PROVIDE ME WITH A SIMPLE CODE? THAT WILL HELP A LOT...

Sergey Alexandrovich Kryukov 24-Mar-11 12:06pm

I don't want to put samples for all cases. You tag your Question as I asked, I'll put the sample accordingly, deal?
--SA

Sergey Alexandrovich Kryukov 24-Mar-11 12:24pm

Please don't shout (ALL-CAPS is shouting, considered impolite in internet.) Where is your tag?
(WPF, WinFroms?)
--SA

Dalek Dave 24-Mar-11 9:53am

Good Answer.

Sergey Alexandrovich Kryukov 24-Mar-11 12:04pm

Thank you, Dalek.
--SA