今天，有个同事问我，怎样在C#中使用全局钩子？以前写的全局钩子都是用unmanaged C或C++写个DLL来实现，可大家都知道，C#是基于.Net Framework的，是managed，怎么实现全局钩子呢？于是开始到网上搜索，好不容易找到一篇，318804 - HOW TO: Set a Windows Hook in Visual C# .NET，里面详细的说明了如何使用鼠标钩子捕获鼠标的移动等，可是，它只能在Application里起作用，出了Application就没用了，就是说它还是没有实现全局钩子，而且文章结尾处说：“Global Hooks are not supported in the .NET Framework...”，这可怎么办呢？
别担心，办法总是有的，经过一番摸索以后，发现WH_KEYBORAD_LL和WH_MOUSE_LL这两个low-level的hook可以被安装成全局的，这就好办了，我们不妨用这两个low-level的hook替换掉WH_KEYBORAD和WH_MOUSE，于是开始测试。结果成功了，在C#里实现了全局钩子。
我们来看一下主要代码段。
首先倒入所需要的windows函数，主要有三个，SetWindowsHookEX用来安装钩子，UnhookWindowsHookEX用来卸载钩子以及CallNextHookEX用来将hook信息传递到链表中下一个hook处理过程。
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall, SetLastError = true)] private static extern int SetWindowsHookEx( int idHook, HookProc lpfn, IntPtr hMod, int dwThreadId);[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall, SetLastError = true)] private static extern int UnhookWindowsHookEx(int idHook);[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)] private static extern int CallNextHookEx( int idHook, int nCode, int wParam, IntPtr lParam); private const int WH_MOUSE_LL = 14; private const int WH_KEYBOARD_LL = 13;//install hook hMouseHook = SetWindowsHookEx( WH_MOUSE_LL, //原来是WH_MOUSE MouseHookProcedure, Marshal.GetHINSTANCE( Assembly.GetExecutingAssembly().GetModules()[0]), 0);//install hook hKeyboardHook = SetWindowsHookEx( WH_KEYBOARD_LL, //原来是WH_KEYBORAD KeyboardHookProcedure, Marshal.GetHINSTANCE( Assembly.GetExecutingAssembly().GetModules()[0]), 0);
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private int MouseHookProc(int nCode, int wParam, IntPtr lParam) { // if ok and someone listens to our events if ((nCode >= 0) && (OnMouseActivity != null)) { //Marshall the data from callback. MouseLLHookStruct mouseHookStruct = (MouseLLHookStruct)Marshal.PtrToStructure(lParam, typeof(MouseLLHookStruct)); //detect button clicked MouseButtons button = MouseButtons.None; short mouseDelta = 0; switch (wParam) { case WM_LBUTTONDOWN: //case WM_LBUTTONUP: //case WM_LBUTTONDBLCLK: button = MouseButtons.Left; break; case WM_RBUTTONDOWN: //case WM_RBUTTONUP: //case WM_RBUTTONDBLCLK: button = MouseButtons.Right; break; case WM_MOUSEWHEEL: //If the message is WM_MOUSEWHEEL, the high-order word of mouseData member is the wheel delta. //One wheel click is defined as WHEEL_DELTA, which is 120. //(value >> 16) & 0xffff; retrieves the high-order word from the given 32-bit value mouseDelta = (short)((mouseHookStruct.mouseData >> 16) & 0xffff); //TODO: X BUTTONS (I havent them so was unable to test) //If the message is WM_XBUTTONDOWN, WM_XBUTTONUP, WM_XBUTTONDBLCLK, WM_NCXBUTTONDOWN, WM_NCXBUTTONUP, //or WM_NCXBUTTONDBLCLK, the high-order word specifies which X button was pressed or released, //and the low-order word is reserved. This value can be one or more of the following values. //Otherwise, mouseData is not used. break; } //double clicks int clickCount = 0; if (button != MouseButtons.None) if (wParam == WM_LBUTTONDBLCLK || wParam == WM_RBUTTONDBLCLK) clickCount = 2; else clickCount = 1; //generate event MouseEventArgs e = new MouseEventArgs( button, clickCount, mouseHookStruct.pt.x, mouseHookStruct.pt.y, mouseDelta); //raise it OnMouseActivity(this, e); } //call next hook return CallNextHookEx(hMouseHook, nCode, wParam, lParam); } |
private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam)
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