作为我正在研究的媒体播放器应用程序的一部分,我想要连接媒体控制键的全局按键(播放,跳过,跳回等).
我一直在寻找大约2个小时试图寻找解决方案 – 但我找不到一个有效的方法.我发现了几个关于同一件事的Stackoverflow答案,但没有一个有效.
我尝试了MouseKeyHook NuGet包,但它永远不会触发事件.我也尝试了FMUtils.KeyboardHook软件包,但同样的事情发生了,除了它在控制台中打印,它在启动后立即关闭了钩子 – 我不知道为什么,查看源代码之后的事件.
我试图得到这个代码项目项目http://www.codeproject.com/Articles/18638/Using-Window-Messages-to-Implement-Global-System-H,但我甚至无法运行演示,这两个演示只是抛出了我无法追踪的奇怪错误.
我的问题是,在我的Winforms应用程序没有聚焦时,我可以用来捕获键盘按下的.net 4.0中的键盘按键的工作方式是什么？
解决方法
以下是我过去十年中用于多个项目的代码.应该没有问题(对于Windows上的任何.Net版本).希望它能帮到你.
public class KeyboardHook : IDisposable
{
bool Global = false;
public delegate void LocalKeyEventHandler(Keys key,bool Shift,bool Ctrl,bool Alt);
public event LocalKeyEventHandler KeyDown;
public event LocalKeyEventHandler KeyUp;
public delegate int CallbackDelegate(int Code,int W,int L);
[StructLayout(LayoutKind.Sequential,CharSet = CharSet.Ansi)]
public struct KBDLLHookStruct
{
public Int32 vkCode;
public Int32 scanCode;
public Int32 flags;
public Int32 time;
public Int32 dwExtraInfo;
}
[DllImport("user32",CallingConvention = CallingConvention.StdCall)]
private static extern int SetWindowsHookEx(HookType idHook,CallbackDelegate lpfn,int hInstance,int threadId);
[DllImport("user32",CallingConvention = CallingConvention.StdCall)]
private static extern bool UnhookWindowsHookEx(int idHook);
[DllImport("user32",CallingConvention = CallingConvention.StdCall)]
private static extern int CallNextHookEx(int idHook,int nCode,int wParam,int lParam);
[DllImport("kernel32.dll",CallingConvention = CallingConvention.StdCall)]
private static extern int GetCurrentThreadId();
public enum HookType : int
{
WH_JOURNALRECORD = 0,WH_JOURNALPLAYBACK = 1,WH_KEYBOARD = 2,WH_GETMESSAGE = 3,WH_CALLWNDPROC = 4,WH_CBT = 5,WH_SYSMSGFILTER = 6,WH_MOUSE = 7,WH_HARDWARE = 8,WH_DEBUG = 9,WH_SHELL = 10,WH_FOREGROUNDIDLE = 11,WH_CALLWNDPROCRET = 12,WH_KEYBOARD_LL = 13,WH_MOUSE_LL = 14
}
private int HookID = 0;
CallbackDelegate TheHookCB = null;
//Start hook
public KeyboardHook(bool Global)
{
this.Global = Global;
TheHookCB = new CallbackDelegate(KeybHookProc);
if (Global)
{
HookID = SetWindowsHookEx(HookType.WH_KEYBOARD_LL,TheHookCB,//0 for local hook. eller hwnd til user32 for global
0); //0 for global hook. eller thread for hooken
}
else
{
HookID = SetWindowsHookEx(HookType.WH_KEYBOARD,//0 for local hook. or hwnd to user32 for global
GetCurrentThreadId()); //0 for global hook. or thread for the hook
}
}
bool IsFinalized = false;
~KeyboardHook()
{
if (!IsFinalized)
{
UnhookWindowsHookEx(HookID);
IsFinalized = true;
}
}
public void Dispose()
{
if (!IsFinalized)
{
UnhookWindowsHookEx(HookID);
IsFinalized = true;
}
}
//The listener that will trigger events
private int KeybHookProc(int Code,int L)
{
KBDLLHookStruct LS = new KBDLLHookStruct();
if (Code < 0)
{
return CallNextHookEx(HookID,Code,W,L);
}
try
{
if (!Global)
{
if (Code == 3)
{
IntPtr ptr = IntPtr.Zero;
int keydownup = L >> 30;
if (keydownup == 0)
{
if (KeyDown != null) KeyDown((Keys)W,GetShiftPressed(),GetCtrlPressed(),GetAltPressed());
}
if (keydownup == -1)
{
if (KeyUp != null) KeyUp((Keys)W,GetAltPressed());
}
//System.Diagnostics.Debug.WriteLine("Down: " + (Keys)W);
}
}
else
{
KeyEvents kEvent = (KeyEvents)W;
Int32 vkCode = Marshal.ReadInt32((IntPtr)L); //Leser vkCode som er de første 32 bits hvor L peker.
if (kEvent != KeyEvents.KeyDown && kEvent != KeyEvents.KeyUp && kEvent != KeyEvents.SKeyDown && kEvent != KeyEvents.SKeyUp)
{
}
if (kEvent == KeyEvents.KeyDown || kEvent == KeyEvents.SKeyDown)
{
if (KeyDown != null) KeyDown((Keys)vkCode,GetAltPressed());
}
if (kEvent == KeyEvents.KeyUp || kEvent == KeyEvents.SKeyUp)
{
if (KeyUp != null) KeyUp((Keys)vkCode,GetAltPressed());
}
}
}
catch (Exception)
{
//Ignore all errors...
}
return CallNextHookEx(HookID,L);
}
public enum KeyEvents
{
KeyDown = 0x0100,KeyUp = 0x0101,SKeyDown = 0x0104,SKeyUp = 0x0105
}
[DllImport("user32.dll")]
static public extern short GetKeyState(System.Windows.Forms.Keys nVirtKey);
public static bool GetCapslock()
{
return Convert.ToBoolean(GetKeyState(System.Windows.Forms.Keys.CapsLock)) & true;
}
public static bool GetNumlock()
{
return Convert.ToBoolean(GetKeyState(System.Windows.Forms.Keys.NumLock)) & true;
}
public static bool GetScrollLock()
{
return Convert.ToBoolean(GetKeyState(System.Windows.Forms.Keys.Scroll)) & true;
}
public static bool GetShiftPressed()
{
int state = GetKeyState(System.Windows.Forms.Keys.ShiftKey);
if (state > 1 || state < -1) return true;
return false;
}
public static bool GetCtrlPressed()
{
int state = GetKeyState(System.Windows.Forms.Keys.ControlKey);
if (state > 1 || state < -1) return true;
return false;
}
public static bool GetAltPressed()
{
int state = GetKeyState(System.Windows.Forms.Keys.Menu);
if (state > 1 || state < -1) return true;
return false;
}
}
测试应用：
static class Program
{
[STAThread]
static void Main()
{
var kh = new KeyboardHook(true);
kh.KeyDown += Kh_KeyDown;
Application.Run();
}
private static void Kh_KeyDown(Keys key,bool Alt)
{
Debug.WriteLine("The Key: " + key);
}
}
它可以用一些代码清理,但我没有打扰,因为它的工作原理.
