Set global hotkeys using C#
Please note that this code will not trigger events in console application projects. You have to use WinForms project for events to fire.
This is the correct code:
public sealed class KeyboardHook : IDisposable
{
// Registers a hot key with Windows.
[DllImport("user32.dll")]
private static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers, uint vk);
// Unregisters the hot key with Windows.
[DllImport("user32.dll")]
private static extern bool UnregisterHotKey(IntPtr hWnd, int id);
/// <summary>
/// Represents the window that is used internally to get the messages.
/// </summary>
private class Window : NativeWindow, IDisposable
{
private static int WM_HOTKEY = 0x0312;
public Window()
{
// create the handle for the window.
this.CreateHandle(new CreateParams());
}
/// <summary>
/// Overridden to get the notifications.
/// </summary>
/// <param name="m"></param>
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
// check if we got a hot key pressed.
if (m.Msg == WM_HOTKEY)
{
// get the keys.
Keys key = (Keys)(((int)m.LParam >> 16) & 0xFFFF);
ModifierKeys modifier = (ModifierKeys)((int)m.LParam & 0xFFFF);
// invoke the event to notify the parent.
if (KeyPressed != null)
KeyPressed(this, new KeyPressedEventArgs(modifier, key));
}
}
public event EventHandler<KeyPressedEventArgs> KeyPressed;
#region IDisposable Members
public void Dispose()
{
this.DestroyHandle();
}
#endregion
}
private Window _window = new Window();
private int _currentId;
public KeyboardHook()
{
// register the event of the inner native window.
_window.KeyPressed += delegate(object sender, KeyPressedEventArgs args)
{
if (KeyPressed != null)
KeyPressed(this, args);
};
}
/// <summary>
/// Registers a hot key in the system.
/// </summary>
/// <param name="modifier">The modifiers that are associated with the hot key.</param>
/// <param name="key">The key itself that is associated with the hot key.</param>
public void RegisterHotKey(ModifierKeys modifier, Keys key)
{
// increment the counter.
_currentId = _currentId + 1;
// register the hot key.
if (!RegisterHotKey(_window.Handle, _currentId, (uint)modifier, (uint)key))
throw new InvalidOperationException("Couldn’t register the hot key.");
}
/// <summary>
/// A hot key has been pressed.
/// </summary>
public event EventHandler<KeyPressedEventArgs> KeyPressed;
#region IDisposable Members
public void Dispose()
{
// unregister all the registered hot keys.
for (int i = _currentId; i > 0; i--)
{
UnregisterHotKey(_window.Handle, i);
}
// dispose the inner native window.
_window.Dispose();
}
#endregion
}
/// <summary>
/// Event Args for the event that is fired after the hot key has been pressed.
/// </summary>
public class KeyPressedEventArgs : EventArgs
{
private ModifierKeys _modifier;
private Keys _key;
internal KeyPressedEventArgs(ModifierKeys modifier, Keys key)
{
_modifier = modifier;
_key = key;
}
public ModifierKeys Modifier
{
get { return _modifier; }
}
public Keys Key
{
get { return _key; }
}
}
/// <summary>
/// The enumeration of possible modifiers.
/// </summary>
[Flags]
public enum ModifierKeys : uint
{
Alt = 1,
Control = 2,
Shift = 4,
Win = 8
}
to use (i had to edit the modifier keys to cast them (modifier)1 (modifier)2 etc
public partial class Form1 : Form
{
KeyboardHook hook = new KeyboardHook();
public Form1()
{
InitializeComponent();
// register the event that is fired after the key press.
hook.KeyPressed +=
new EventHandler<KeyPressedEventArgs>(hook_KeyPressed);
// register the control + alt + F12 combination as hot key.
hook.RegisterHotKey(ModifierKeys.Control | ModifierKeys.Alt,
Keys.F12);
}
void hook_KeyPressed(object sender, KeyPressedEventArgs e)
{
// show the keys pressed in a label.
label1.Text = e.Modifier.ToString() + " + " + e.Key.ToString();
}
}
I took the answer from AaronLS and rewrote it a bit for a simple one-liner registration.
The Registration:
GlobalHotKey.RegisterHotKey("Alt + Shift + S", () => DoSomething());
The Class:
using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Windows.Input;
public class GlobalHotKey : IDisposable
{
/// <summary>
/// Registers a global hotkey
/// </summary>
/// <param name="aKeyGesture">e.g. Alt + Shift + Control + Win + S</param>
/// <param name="aAction">Action to be called when hotkey is pressed</param>
/// <returns>true, if registration succeeded, otherwise false</returns>
public static bool RegisterHotKey(string aKeyGestureString, Action aAction)
{
var c = new KeyGestureConverter();
KeyGesture aKeyGesture = (KeyGesture)c.ConvertFrom(aKeyGestureString);
return RegisterHotKey(aKeyGesture.Modifiers, aKeyGesture.Key, aAction);
}
public static bool RegisterHotKey(ModifierKeys aModifier, Key aKey, Action aAction)
{
if(aModifier == ModifierKeys.None)
{
throw new ArgumentException("Modifier must not be ModifierKeys.None");
}
if (aAction is null)
{
throw new ArgumentNullException(nameof(aAction));
}
System.Windows.Forms.Keys aVirtualKeyCode = (System.Windows.Forms.Keys)KeyInterop.VirtualKeyFromKey(aKey);
currentID = currentID + 1;
bool aRegistered = RegisterHotKey(window.Handle, currentID,
(uint)aModifier | MOD_NOREPEAT,
(uint)aVirtualKeyCode);
if(aRegistered)
{
registeredHotKeys.Add(new HotKeyWithAction(aModifier, aKey, aAction));
}
return aRegistered;
}
public void Dispose()
{
// unregister all the registered hot keys.
for (int i = currentID; i > 0; i--)
{
UnregisterHotKey(window.Handle, i);
}
// dispose the inner native window.
window.Dispose();
}
static GlobalHotKey()
{
window.KeyPressed += (s, e) =>
{
registeredHotKeys.ForEach(x =>
{
if (e.Modifier == x.Modifier && e.Key == x.Key)
{
x.Action();
}
});
};
}
private static readonly InvisibleWindowForMessages window = new InvisibleWindowForMessages();
private static int currentID;
private static uint MOD_NOREPEAT = 0x4000;
private static List<HotKeyWithAction> registeredHotKeys = new List<HotKeyWithAction>();
private class HotKeyWithAction
{
public HotKeyWithAction(ModifierKeys modifier, Key key, Action action)
{
Modifier = modifier;
Key = key;
Action = action;
}
public ModifierKeys Modifier { get; }
public Key Key { get; }
public Action Action { get; }
}
// Registers a hot key with Windows.
[DllImport("user32.dll")]
private static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers, uint vk);
// Unregisters the hot key with Windows.
[DllImport("user32.dll")]
private static extern bool UnregisterHotKey(IntPtr hWnd, int id);
private class InvisibleWindowForMessages : System.Windows.Forms.NativeWindow, IDisposable
{
public InvisibleWindowForMessages()
{
CreateHandle(new System.Windows.Forms.CreateParams());
}
private static int WM_HOTKEY = 0x0312;
protected override void WndProc(ref System.Windows.Forms.Message m)
{
base.WndProc(ref m);
if (m.Msg == WM_HOTKEY)
{
var aWPFKey = KeyInterop.KeyFromVirtualKey(((int)m.LParam >> 16) & 0xFFFF);
ModifierKeys modifier = (ModifierKeys)((int)m.LParam & 0xFFFF);
if (KeyPressed != null)
{
KeyPressed(this, new HotKeyPressedEventArgs(modifier, aWPFKey));
}
}
}
public class HotKeyPressedEventArgs : EventArgs
{
private ModifierKeys _modifier;
private Key _key;
internal HotKeyPressedEventArgs(ModifierKeys modifier, Key key)
{
_modifier = modifier;
_key = key;
}
public ModifierKeys Modifier
{
get { return _modifier; }
}
public Key Key
{
get { return _key; }
}
}
public event EventHandler<HotKeyPressedEventArgs> KeyPressed;
#region IDisposable Members
public void Dispose()
{
this.DestroyHandle();
}
#endregion
}
}