1.实现钩子函数
钩子(Hook)的实现需要三个主要的函数和一个委托
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr
hInstance, int threadId);//设置系统钩子
[DllImport("user32.dll",
CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
private static extern bool UnhookWindowsHookEx(int idHook);//卸载系统钩子
[DllImport("user32.dll",
CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
public static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam,
IntPtr lParam);//调用下一个钩子函数
public delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);//用于处理Hook住的消息
当我们在执行一个操作的时候,首先不是由我们的窗体获得消息,而是系统获得,然后系统再把消息发送到对应的窗体,Hook就是在窗体获取到信息之前抓住信息,然后对信息进行处理,然后可以传递给船体继续执行,或者就不传递给窗体
当在HookProc处理消息的时候,如果return 1,那么消息就会被截断,不会再传递到目标窗口,如果return的是CallNextHookEx那么就会继续调用下一个钩子,如果下面没有钩子了,那么消息就会被传递到目标窗体进行处理
SetWindowsHookEx第一个参数是需要勾住的消息类型,总共14种消息类型,如下
public
const int WH_JOURNALRECORD = 0;
public const int constWH_JOURNALPLAYBACK = 1;
public const int WH_KEYBOARD = 2;
public const int WH_GETMESSAGE = 3;
public const int WH_CALLWNDPROC = 4;
public const int WH_CBT = 5;
public const int WH_SYSMSGFILTER = 6;
public const int WH_MOUSE = 7;
public const int WH_HARDWARE = 8;
public const int WH_DEBUG = 9;
public const int WH_SHELL = 10;
public const int WH_FOREGROUNDIDLE = 11;
public const int WH_CALLWNDPROCRET = 12;
public const int WH_KEYBOARD_LL = 13;
public const int WH_MOUSE_LL = 14;
第二个参数就是HookProc委托,用于对钩住的消息进行处理,
第三个参数是需要钩住的实例的句柄,最后一个是钩住的线程,如果是0则是全局钩住
返回值为抓住的钩子的ID
UnhookWindowsHookEx卸载掉钩子,参数为上面返回的ID
辅助函数
[DllImport("kernel32.dll")]
public static extern IntPtr GetModuleHandle(string name);//根据模块名称获取到对应的句柄
[DllImport("user32.dll", EntryPoint = "FindWindow")]
private extern static IntPtr FindWindow(string lpClassName, string lpWindowName);//查询一个窗体
[DllImport("User32.dll", EntryPoint = "FindWindowEx")]
private static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpClassName, string lpWindowName);//获取窗体中的所有子窗体(文本框,按钮等,都属于窗体)
[DllImport("user32.dll")]
public static extern int EnumChildWindows(IntPtr hWndParent, CallBack lpfn, int lParam);//枚举窗体中的所有子窗体
public delegate bool CallBack(IntPtr hwnd, int lParam);
此委托是EnumChildWindows的回调函数,用于遍历的时候对窗口进行处理
根据Module的名字获取到对应的句柄SetWindowsHookEx的第三个参数可以使用这个函数来获得。
下面是一个示例程序,设置一个全局钩子,作用是,如果输入的字符是小写字母,则直接转换为大写字母。
1.1 HookProc的方法实现
private int MessageHandle(int nCode, Int32 wParam, IntPtr lParam)
{
if (0x100 == wParam || 0x101 == wParam) //如果按键为按下状态,如果没有这句判断,则内部代码会执行两遍,一遍是KeyDown一遍是KeyUp
{
KBDLLHOOKSTRUCT ks = (KBDLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(KBDLLHOOKSTRUCT));
//将所有的小写字母直接加1
if (ks.vkCode >= 65 && ks.vkCode <= 90)
{
string cUpper = Convert.ToChar(ks.vkCode).ToString().ToUpper();
SendMessage(txtHandle, 0x0c, IntPtr.Zero, cUpper);
}
}
return CallNextHookEx(result, nCode, 0, lParam);
}
1.2 KBDLLHOOKSTRUCT结构体(这个结构体因为不同的钩子内容会不一样)
public struct KBDLLHOOKSTRUCT
{
public int vkCode;
public int scanCode;
public int flags;
public int time;
public IntPtr dwExtraInfo;
}
1.3设置钩子和卸载钩子(两个按钮的事件)
private void btnInstallHook_Click(object sender, EventArgs e)
{
HookProc hProc = new HookProc(MessageHandle);
IntPtr cInstance = GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName);
result = SetWindowsHookEx(HookHelper.WH_KEYBOARD_LL, hProc, cInstance, 0);
}
private void btnUnhook_Click(object sender, EventArgs e)
{
UnhookWindowsHookEx(result);
}
辅助方法:为了获取到窗体中的文本框的句柄
//枚举窗体中的子窗体的回调函数
private bool EnumWindow(IntPtr hwnd, int lParam)
{
StringBuilder sb=new StringBuilder();
GetWindowText(hwnd, sb, 10);
if (sb.ToString() == "HookTest")
{
txtHandle = hwnd;
}
return true;
}
2.SendMessage的使用
可以使用SendMessage模拟给发送一条系统消息
[DllImport("user32.dll", EntryPoint = "SendMessage")]
private static extern int SendMessage(IntPtr hwnd, int wMsg, IntPtr wParam, IntPtr lParam);
[DllImport("User32.dll", EntryPoint = "SendMessage")]
private static extern int SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, string lParam);//发送消息,此重载方法可以直接给文本框赋值
下面是一个自动点击按钮和自动给文本框赋值的示例
private void btnTest_Click(object sender, EventArgs e)
{
#region 自动点击按钮
//IntPtr cProcess = FindWindow(null, "测试Hook");
//winHandle = FindWindowEx(cProcess, IntPtr.Zero, null, "点击显示界面");
////SendMessage(winHandle, 0xf5, 0, 0);//0xf5 BM_CLICK 按钮单击对应的消息--经过测试,直接使用0xf5无法实现点击按钮的功能
////测试结果发现,如果想要实现单击按钮的功能,必须先按下鼠标左键,再抬起鼠标左键
//SendMessage(winHandle, 0x201, IntPtr.Zero, IntPtr.Zero);//0x201 WM_LBUTTONDOWN 按下鼠标左键对应的消息
//SendMessage(winHandle, 0x202, IntPtr.Zero, IntPtr.Zero);//0x201 WM_LBUTTONUP 抬起鼠标左键对应的消息
#endregion
#region 自动输入文本
//IntPtr cProcess = FindWindow(null, "Test.txt - 记事本");
//winHandle = FindWindowEx(cProcess, IntPtr.Zero, null, "");
//IntPtr cProcess = FindWindow(null, "测试Hook");
//winHandle = FindWindowEx(cProcess, IntPtr.Zero, null, null);
////winHandle = new IntPtr(0xE10F2);//这种方式是先通过Spy++找到控件的句柄,然后再使用这个句柄进行数据交互(此方法每次重启窗体,对应的句柄都会发生变化)
//SendMessage(txtHandle, 0x0c, IntPtr.Zero, "ABCDEFGHIJKLMN");//0x0c wm_settext 给窗体设置文本
#endregion
}
源代码:https://files.cnblogs.com/files/ckym/HookTest.rar