I need to capture a key press when my program is not in focus. (ie. Ctrl+Alt+J) and trigger an event in my program.
Thus far i have found this dll that appears to be the correct path"
[DllImport("user32.dll")]private static extern int RegisterHotKey(IntPtr hwnd, int id,int fsModifiers, int vk);
[DllImport("user32.dll")] private static extern int UnregisterHotKey(IntPtr hwnd, int id);
请注意，此代码不会触发控制台应用程序项目中的事件。您必须使用 WinForms 项目才能触发事件。
这是正确的代码：
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
}
使用（我必须编辑修饰键来投射它们（修饰符）1（修饰符）2等
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();
}
}
我从 AaronLS 那里得到了答案，并为一个简单的单行注册重写了一点。
注册：
GlobalHotKey.RegisterHotKey("Alt + Shift + S", () => DoSomething());
班上：
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
}
}
Imports System.Runtime.InteropServices
Public NotInheritable Class KeyboardHook
Implements IDisposable
' Registers a hot key with Windows.
<DllImport("user32.dll")> _
Private Shared Function RegisterHotKey(hWnd As IntPtr, id As Integer, fsModifiers As UInteger, vk As UInteger) As Boolean
End Function
' Unregisters the hot key with Windows.
<DllImport("user32.dll")> _
Private Shared Function UnregisterHotKey(hWnd As IntPtr, id As Integer) As Boolean
End Function
''' <summary>
''' Represents the window that is used internally to get the messages.
''' </summary>
Private Class Window
Inherits NativeWindow
Implements IDisposable
Private Shared WM_HOTKEY As Integer = &H312
Public Sub New()
' create the handle for the window.
Me.CreateHandle(New CreateParams())
End Sub
Public Event KeyPressed As EventHandler(Of KeyPressedEventArgs)
''' <summary>
''' Overridden to get the notifications.
''' </summary>
''' <param name="m"></param>
Protected Overrides Sub WndProc(ByRef m As Message)
MyBase.WndProc(m)
' check if we got a hot key pressed.
If m.Msg = WM_HOTKEY Then
' get the keys.
Dim key As Keys = DirectCast((CInt(m.LParam) >> 16) And &HFFFF, Keys)
Dim modifier As ModifierKeys = DirectCast(CUInt(CInt(m.LParam) And &HFFFF), ModifierKeys)
' invoke the event to notify the parent.
RaiseEvent KeyPressed(Me, New KeyPressedEventArgs(modifier, key))
End If
End Sub
#Region " IDisposable Members"
Public Sub Dispose() Implements IDisposable.Dispose
Me.DestroyHandle()
End Sub
#End Region
End Class
Private _window As New Window()
Private _currentId As Integer
Public Sub New()
' register the event of the inner native window.
AddHandler _window.KeyPressed, Sub(sender As Object, args As KeyPressedEventArgs)
RaiseEvent KeyPressed(Me, args)
End Sub
End Sub
''' <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 Sub RegisterHotKey(modifier As ModifierKeys, key As Keys)
' increment the counter.
_currentId = _currentId + 1
' register the hot key.
If Not RegisterHotKey(_window.Handle, _currentId, DirectCast(modifier, UInteger), CUInt(key)) Then
'Throw New InvalidOperationException("Couldn’t register the hot key.")
'or use MsgBox("Couldn’t register the hot key.")
End If
End Sub
''' <summary>
''' A hot key has been pressed.
''' </summary>
Public Event KeyPressed As EventHandler(Of KeyPressedEventArgs)
#Region " IDisposable Members"
Public Sub Dispose() Implements IDisposable.Dispose
' unregister all the registered hot keys.
Dim i As Integer = _currentId
While i > 0
UnregisterHotKey(_window.Handle, i)
System.Math.Max(System.Threading.Interlocked.Decrement(i), i + 1)
End While
' dispose the inner native window.
_window.Dispose()
End Sub
#End Region
End Class
''' <summary>
''' Event Args for the event that is fired after the hot key has been pressed.
''' </summary>
Public Class KeyPressedEventArgs
Inherits EventArgs
Private _modifier As ModifierKeys
Private _key As Keys
Friend Sub New(modifier As ModifierKeys, key As Keys)
_modifier = modifier
_key = key
End Sub
Public ReadOnly Property Modifier() As ModifierKeys
Get
Return _modifier
End Get
End Property
Public ReadOnly Property Key() As Keys
Get
Return _key
End Get
End Property
End Class
''' <summary>
''' The enumeration of possible modifiers.
''' </summary>
<Flags> _
Public Enum ModifierKeys As UInteger
Alt = 1
Control = 2
Shift = 4
Win = 8
End Enum
任务：
Application1中可以将其视为树的根）。AddGlobalHotkeySupport()应用程序的初始化阶段。RemoveGlobalHotkeySupport()应用程序的完成阶段。代码：
Public Sub AddGlobalHotkeySupport() 'TODO: call this at initialization of the application
' register the event that is fired after the key press.
AddHandler hook.KeyPressed, AddressOf hook_KeyPressed
' register the control + alt + F12 combination as hot key.
hook.RegisterHotKey(Application1.ModifierKeys.Control Or Application1.ModifierKeys.Alt, Keys.F12)
End Sub
Public Sub RemoveGlobalHotkeySupport() 'TODO: call this at finalization of the application
' unregister all registered hot keys.
hook.Dispose()
End Sub
Private Sub hook_KeyPressed(sender As Object, e As KeyPressedEventArgs)
' show the keys pressed in a label.
MsgBox(e.Modifier.ToString() + " + " + e.Key.ToString())
End Sub