C#实现全局钩子步骤
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，怎么让C#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#实现全局钩子。
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\",CharSetCharSet=CharSet.Auto,
- CallingConventionCallingConvention=CallingConvention.StdCall,SetLastError=true)]
- privatestaticexternintSetWindowsHookEx(
- intidHook,
- HookProclpfn,
- IntPtrhMod,
- intdwThreadId);
- [DllImport(\"user32.dll\",CharSetCharSet=CharSet.Auto,
- CallingConventionCallingConvention=CallingConvention.StdCall,SetLastError=true)]
- privatestaticexternintUnhookWindowsHookEx(intidHook);
- [DllImport(\"user32.dll\",CharSetCharSet=CharSet.Auto,
- CallingConventionCallingConvention=CallingConvention.StdCall)]
- privatestaticexternintCallNextHookEx(
- intidHook,
- intnCode,
- intwParam,
- IntPtrlParam);
有关这两个low-level hook在Winuser.h中的定义
- ///WindowsNT/2000/XP:
Installsahookprocedurethatmonitorslow-levelmouseinputevents.- ///[Page]
- privateconstintWH_MOUSE_LL=14;
- /**////
- ///WindowsNT/2000/XP:
Installsahookprocedurethatmonitorslow-levelkeyboardinputevents.- ///
- privateconstintWH_KEYBOARD_LL=13;
在安装全局钩子的时候，我们就要做替换了，将WH_MOUSE和WH_KEYBORAD分别换成WH_MOUSE_LL和WH_KEYBORAD_LL：
- //installhook
- hMouseHook=SetWindowsHookEx(
- WH_MOUSE_LL, //原来是WH_MOUSE
- MouseHookProcedure,
- Marshal.GetHINSTANCE(
- Assembly.GetExecutingAssembly().GetModules()[0]),
- 0);
- //installhook
- hKeyboardHook=SetWindowsHookEx(
- WH_KEYBOARD_LL,//原来是WH_KEYBORAD
- KeyboardHookProcedure,
- Marshal.GetHINSTANCE(
- Assembly.GetExecutingAssembly().GetModules()[0]),
- 0);[Page]
这样替换了之后，我们就可以C#实现全局钩子了，而且，不需要写DLL。看一下程序运行情况：
下面是关于鼠标和键盘的两个Callback函数：
- 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; [Page]
- 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,[Page]- //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;
- }
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