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Net实现钩子函数(Hook)以及通过SendMessage实现自动点击按钮和给文本框赋值

  • 作者: 仅此而已23644505
  • 来源: 51数据库
  • 2021-10-19

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=utf-8.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=utf-8.auto, callingconvention = callingconvention.stdcall)]
private static extern bool unhookwindowshookex(int idhook);//卸载系统钩子

[dllimport("user32.dll", charset=utf-8.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

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