C# capture main form keyboard events

Question

How to catch keyboard events of the WinForm main form, where other controls are. So I want to catch one event Ctrl + S and doesn't matter where focus is. But without Pinvoke (hooks and such ...) Only .NET managed internal power.

possible duplicate of [Best way to implement keyboard shortcuts in winforms?](http://stackoverflow.com/questions/400113/best-way-to-implement-keyboard-shortcuts-in-winforms) — Hans Passant, Jul 14 '11 at 17:27

MikeM · Answer 1 · 2011-07-14T17:55:42.007

12

the Form Class (System.Windows.Forms) has OnKeyDown, OnKeyPress, and OnKeyUp event methods that you can use to detect Ctrl + S

use the KeyEventArgs in those methods to determine which keys were pressed

EDIT

be sure to enable Form.KeyPreview = true; so the form will capture the events regardless of focus.

edited Jul 14 '11 at 17:55

answered Jul 14 '11 at 17:24

MikeM

27,227
4
64
80

You missed the "doesn't matter where focus is" requirement. – Hans Passant Jul 14 '11 at 17:27
Did you read: "So I want to catch one event Ctrl + S and doesn't matter where focus is". Please, read carefully. – Jul 14 '11 at 17:30

score 11 · Accepted Answer · edited Apr 04 '13 at 09:29

Try this code. Use the interface IMessageFilter you can filter any ctrl+key.

public partial class Form1 : 
    Form,
    IMessageFilter
{
    public Form1()
    {
        InitializeComponent();

        Application.AddMessageFilter(this);
        this.FormClosed += new FormClosedEventHandler(this.Form1_FormClosed);
    }

    private void Form1_FormClosed(object sender, FormClosedEventArgs e)
    {
        Application.RemoveMessageFilter(this);
    }

    public bool PreFilterMessage(ref Message m)
    {
        //here you can specify  which key you need to filter

        if (m.Msg == 0x0100 && (Keys)m.WParam.ToInt32() == Keys.S &&
            ModifierKeys == Keys.Control) 
        {
            return true;
        }
        else
        {
            return false;
        }
    }
}

I tested this and worked for me.

score 1 · Answer 3 · answered Jul 14 '11 at 17:31

1

Handle the KeyDown on the form and all its controls.

private void OnFormLoad(object sender, EventArgs e)
{
    this.KeyDown += OnKeyDown;
    foreach (Control control in this.Controls)
    {
        control.KeyDown += OnKeyDown;
    }
}

private void OnKeyDown(object sender, KeyEventArgs e)
{
    if (e.Control)
    {
        if (e.KeyValue == (int)Keys.S)
        {
            Console.WriteLine("ctrl + s");
        }
    }
}

answered Jul 14 '11 at 17:31

Jalal Said

15,906
7
45
68

Did you read: "So I want to catch one event Ctrl + S and doesn't matter where focus is". Please, read carefully. – Jul 14 '11 at 17:32
@Robb: Yes I read that, but I assumed that the phase `doesn't matter where focus is` referring to the inside the form or its controls so no matter if the focus where on for example a `textBox1` or in the form. isn't that you meant? – Jalal Said Jul 14 '11 at 17:39
@Robb: did you notice the question on my previous comment? – Jalal Said Jul 14 '11 at 17:50
Jalal, yas I meant that... but if this question is only about KeyDown event, then I wouldn't ask. I used to apply P/Invoke Keyboard hook Proc before, and Asish's answer was exectly what I was looking for. – Jul 14 '11 at 21:37

score 1 · Answer 4 · answered Jul 14 '11 at 17:38

You may add a MenuStrip and then create a menu strip item named save and give it a short cut Ctrl + S. Add a event handler for that. This will fire even if the focus is on other control on the form. If you don't like to see the MenuStrip; you can set visible = false too. I must admit this is ugly.

C# capture main form keyboard events

4 Answers4

Linked

Related