如何挂钩应用程序？

Question

我正试图在我的C#应用​​程序中挂钩创建一个窗口.

static IntPtr hhook = IntPtr.Zero;
static NativeMethods.HookProc hhookProc;

static void Main(string[] args)
{
    // Dummy.exe is a form with a button that opens a MessageBox when clicking on it.
    Process dummy = Process.Start(@"Dummy.exe");

    try
    {
        hhookProc = new NativeMethods.HookProc(Hook);
        IntPtr hwndMod = NativeMethods.GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName);
        hhook = NativeMethods.SetWindowsHookEx(HookType.WH_CBT, hhookProc, hwndMod, (uint)AppDomain.GetCurrentThreadId());

        Console.WriteLine("hhook valid? {0}", hhook != IntPtr.Zero);

        while (!dummy.HasExited)
            dummy.WaitForExit(500);                
    }
    finally
    {
        if(hhook != IntPtr.Zero)
            NativeMethods.UnhookWindowsHookEx(hhook);
    }
}

static int Hook(int nCode, IntPtr wParam, IntPtr lParam)
{
    Console.WriteLine("Hook()");
    return NativeMethods.CallNextHookEx(hhook, nCode, wParam, lParam);
}

问题是,当点击我的按钮(在Dummy.exe中)时,我从不进入我的Hook,我做错了什么？

谢谢.

---

编辑

Program.cs中

using System;
using System.Diagnostics;

namespace Hooker
{
    class Program
    {
        static IntPtr hhook = IntPtr.Zero;
        static NativeMethods.HookProc hhookProc;

        static void Main(string[] args)
        {
            Process dummy = Process.Start(@"Dummy.exe");

            try
            {
                hhookProc = new NativeMethods.HookProc(Hook);
                hhook = NativeMethods.SetWindowsHookEx(HookType.WH_CBT, hhookProc, IntPtr.Zero, 0);

                Console.WriteLine("hhook valid? {0}", hhook != IntPtr.Zero);

                while (!dummy.HasExited)
                    dummy.WaitForExit(500);                
            }
            finally
            {
                if(hhook != IntPtr.Zero)
                    NativeMethods.UnhookWindowsHookEx(hhook);
            }
        }

        static int Hook(int nCode, IntPtr wParam, IntPtr lParam)
        {
            Console.WriteLine("Hook()");
            return NativeMethods.CallNextHookEx(IntPtr.Zero, nCode, wParam, lParam);
        }
    }
}

NativeMethods.cs

namespace Hooker
{
    using System;
    using System.Runtime.InteropServices;

    internal static class NativeMethods
    {
        public delegate int HookProc(int code, IntPtr wParam, IntPtr lParam);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern IntPtr SetWindowsHookEx(HookType hookType, HookProc lpfn, IntPtr hMod, int dwThreadId);
        [DllImport("user32.dll")]
        public static extern int CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);
        [DllImport("user32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool UnhookWindowsHookEx(IntPtr hhk);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern int GetWindowThreadProcessId(IntPtr hwnd, ref int pid);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern IntPtr GetModuleHandle(string lpModuleName);
    }
}

对于虚拟,请执行以下新表格:

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        MessageBox.Show("CONTENT", "TITLE");
    }

Answer 1

像大多数SetWindowsHookEx钩子一样,WH_CBT钩子要求钩子回调存在于一个单独的Win32 DLL中,该DLL将被加载到目标进程中.这基本上要求钩子是用C/C++编写的,C#在这里不起作用.

(低级鼠标和键盘挂钩是此规则的两个例外.也可能在C#中使用其他挂钩,但仅当您挂钩自己的一个线程时,所以dwThreadId是当前进程中线程的id但不是0.我还没有证实这一点.你需要确保你使用的是Win32 threadid,所以使用GetCurrentThreadId可能是最好的选择.)

如果你想要观察从另一个应用程序出现的新窗口,另一种C#友好的方法是使用SetWinEventHook API,指定WINEVENT_OUTOFCONTEXT(这是一个魔术标志,可以将事件传递给您自己的进程,无需使用DLL和使C#在这里可用)和钩子EVENT_OBJECT_CREATE和EVENT_OBJECT_SHOW事件.您可以侦听自己的进程/线程事件,也可以侦听当前桌面上的所有进程/线程.

这将为您提供各种"创建"和显示通知,包括对话框中的子HWND,甚至列表框和类似内容中的项目; 因此,您需要过滤以仅提取顶级HWND的那些:例如.检查idObject == OBJID_WINDOW和idChild == 0; 那个hwnd是可见的(IsVisible())并且是顶级的.

请注意,使用WinEvents要求调用SetWinEventHook的线程正在抽取消息 - 如果它是带有UI的线程,通常就是这种情况.如果没有,您可能需要手动添加消息循环(GetMessage/TranslateMessage).此外,您还希望将GC.KeepAlive()与回调一起使用,以防止在调用UnhookWinEvents之前收集它.