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registerhotkey (user32)

C# Signature:

[return: MarshalAs(UnmanagedType.Bool)]
static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers,
   uint vk);

VB Signature:

Public Declare Function RegisterHotKey Lib "user32" Alias "RegisterHotKey" (ByVal hwnd As Long, ByVal id As Long, ByVal fsModifiers As Long, ByVal vk As Long) As Long Signature:

Declare Auto Function registerhotkey Lib "user32.dll" (Byval handle As IntPtr, ByVal id As Integer, ByVal fsModifier As Integer, ByVal vk As Integer) As Integer

User-Defined Types:




Tips & Tricks:

Please add some!

Sample Code:

    // c#
    public class WindowsShell
        #region fields
        public static int MOD_ALT = 0x1;
        public static int MOD_CONTROL = 0x2;
        public static int MOD_SHIFT = 0x4;
        public static int MOD_WIN = 0x8;
        public static int WM_HOTKEY = 0x312;

        private static extern bool RegisterHotKey(IntPtr hWnd, int id, int fsModifiers, int vlc);

        private static extern bool UnregisterHotKey(IntPtr hWnd, int id);

        private static int keyId;
        public static void RegisterHotKey(Form f, Keys key)
            int modifiers = 0;

            if ((key & Keys.Alt) == Keys.Alt)
                modifiers = modifiers | WindowsShell.MOD_ALT;

            if ((key & Keys.Control) == Keys.Control)
                modifiers = modifiers | WindowsShell.MOD_CONTROL;

            if ((key & Keys.Shift) == Keys.Shift)
                modifiers = modifiers | WindowsShell.MOD_SHIFT;

            Keys k = key & ~Keys.Control & ~Keys.Shift & ~Keys.Alt;

            Func ff = delegate()
                    keyId = f.GetHashCode(); // this should be a key unique ID, modify this if you want more than one hotkey
                    RegisterHotKey((IntPtr)f.Handle, keyId, modifiers, (int)k);

            f.Invoke(ff); // this should be checked if we really need it (InvokeRequired), but it's faster this way

        private delegate void Func();

        public static void UnregisterHotKey(Form f)
                Func ff = delegate()
                    UnregisterHotKey(f.Handle, keyId); // modify this if you want more than one hotkey

                f.Invoke(ff); // this should be checked if we really need it (InvokeRequired), but it's faster this way
            catch (Exception ex)

    public partial class Form1 : Form, IDisposable
        protected override void OnLoad(EventArgs e)
            Keys k = Keys.A | Keys.Control;
            WindowsShell.RegisterHotKey(this, k);

        // CF Note: The WndProc is not present in the Compact Framework (as of vers. 3.5)! please derive from the MessageWindow class in order to handle WM_HOTKEY
        protected override void WndProc(ref Message m)
            base.WndProc(ref m);

            if (m.Msg == WindowsShell.WM_HOTKEY)
                this.Visible = !this.Visible;

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)

Alternative Managed API:

The ManagedWindowsApi project ( provides a

Hotkey class to register global hotkeys.


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