听另一个窗口调整C#中的事件

Question

我正在实现一个小应用程序(观察者),需要将自己"附加"到另一个窗口的底部(观察到).后者不是应用程序内部的窗口.

此时我通过获取窗口的hWnd并在线程中定期查询观察窗口的位置来解决,相应地移动观察者窗口.

然而,这是一个非常不优雅的解决方案.我想做的是听取观察窗口的resize事件,以便观察者只在必要时做出反应.

我假设我应该使用一个钩子,并且我找到了很多方法,但是我对C WinAPI缺乏了解阻碍了我需要创建哪个钩子以及如何(pinvoke/parameters/etc).

我很确定这是非常简单的,你们中的一些熟悉C/C++和WinAPI就可以随时得到答案;)

谢谢

Answer 1

扩展Chris Taylor的答案:您可以使用包含类的ManagedWinApi,而不是自己进行本地互操作Hook.

编辑:使用ManagedWinApi.代码中的某个地方:

Hook MyHook = new Hook(HookType.WH_CALLWNDPROC, false, false);
MyHook.Callback += MyHookCallback;
MyHook StartHook();

对于回调,引用CallWndProc和CWPSTRUCT:

private static int MyHookCallback(int code, IntPtr wParam, IntPtr lParam, ref bool callNext)
{
    if (code >= 0)
    {
        // You will need to define the struct
        var message = (CWPSTRUCT)Marshal.PtrToStructure(lParam, typeof(CWPSTRUCT));
        // Do something with the data
    }
    return 0; // Return value is ignored unless you set callNext to false
}

Answer 2

我在使用的一些代码中遇到了同样的问题，并发现我无法将托管 .DLL 注入到进程中。

我不想编写一个使用 SetWindowsHook 的 C++ 非托管 DLL，所以我使用了 的组合SetWinEventHook，它在窗口开始和结束移动事件时发出信号，并Timer在窗口移动时轮询窗口，使其看起来跟随窗口。移动。

这是一个可以做到这一点的类的（非常简化的）版本（只需用移动窗口或引发事件的代码替换 TODO）。

public class DockingHelper
{
    private readonly uint m_processId, m_threadId;

    private readonly IntPtr m_target;

    // Needed to prevent the GC from sweeping up our callback
    private readonly WinEventDelegate m_winEventDelegate;
    private IntPtr m_hook;

    private Timer m_timer;

    public DockingHelper(string windowName, string className)
    {
        if (windowName == null && className == null) throw new ArgumentException("Either windowName or className must have a value");

        m_target = FindWindow(className, windowName);
        ThrowOnWin32Error("Failed to get target window");

        m_threadId = GetWindowThreadProcessId(m_target, out m_processId);
        ThrowOnWin32Error("Failed to get process id");

        m_winEventDelegate = WhenWindowMoveStartsOrEnds;
    }

    [DllImport("user32.dll", SetLastError = true)]
    private static extern bool GetWindowRect(IntPtr hwnd, out RECT lpRect);

    [DllImport("user32.dll", SetLastError = true)]
    private static extern bool UnhookWinEvent(IntPtr hWinEventHook);

    [DllImport("user32.dll")]
    private static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr hmodWinEventProc, WinEventDelegate lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);

    [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
    private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

    [DllImport("user32.dll", SetLastError = true)]
    private static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint lpdwProcessId);

    private void ThrowOnWin32Error(string message)
    {
        int err = Marshal.GetLastWin32Error();
        if (err != 0)
            throw new Win32Exception(err, message);
    }

    private RECT GetWindowLocation()
    {
        RECT loc;
        GetWindowRect(m_target, out loc);
        if (Marshal.GetLastWin32Error() != 0)
        {
            // Do something useful with this to handle if the target window closes, etc.
        }
        return loc;
    }

    public void Subscribe()
    {
        // 10 = window move start, 11 = window move end, 0 = fire out of context
        m_hook = SetWinEventHook(10, 11, m_target, m_winEventDelegate, m_processId, m_threadId, 0);
    }

    private void PollWindowLocation(object state)
    {
        var location = GetWindowLocation();
        // TODO: Reposition your window with the values from location (or fire an event with it attached)
    }

    public void Unsubscribe()
    {
        UnhookWinEvent(m_hook);
    }

    private void WhenWindowMoveStartsOrEnds(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
    {
        if (hwnd != m_target) // We only want events from our target window, not other windows owned by the thread.
            return;

        if (eventType == 10) // Starts
        {
            m_timer = new Timer(PollWindowLocation, null, 10, Timeout.Infinite);
            // This is always the original position of the window, so we don't need to do anything, yet.
        }
        else if (eventType == 11)
        {
            m_timer.Dispose();
            m_timer = null;
            var location = GetWindowLocation();
            // TODO: Reposition your window with the values from location (or fire an event with it attached)
        }
    }

    [StructLayout(LayoutKind.Sequential)]
    private struct RECT
    {
        public int Left, Top, Right, Bottom;
    }

    private delegate void WinEventDelegate(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime);
}