.net - 如何在c#中调用GetGUIThreadInfo

Question

我有一个窗口句柄，并试图通过传入窗口的进程 ID 来调用 GetGUIThreadInfo。我总是在调用 GetGUIThreadInfo 时收到错误“参数不正确”，我可以找出原因。有没有人让这个工作？

[DllImport("user32.dll", SetLastError = true)]
public static extern bool GetGUIThreadInfo(unit hTreadID, ref GUITHREADINFO lpgui);

[DllImport("user32.dll")]
public static extern uint GetWindowThreadProcessId(unit hwnd, out uint lpdwProcessId);

[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
    public int iLeft;
    public int iTop;
    public int iRight;
    public int iBottom;
}

[StructLayout(LayoutKind.Sequential)]
public struct GUITHREADINFO
{
    public int cbSize;
    public int flags;
    public IntPtr hwndActive;
    public IntPtr hwndFocus;
    public IntPtr hwndCapture;
    public IntPtr hwndMenuOwner;
    public IntPtr hwndMoveSize;
    public IntPtr hwndCaret;
    public RECT rectCaret;
}

public static bool GetInfo(unit hwnd, out GUITHREADINFO lpgui)
{ 
    uint lpdwProcessId;
    GetWindowThreadProcessId(hwnd, out lpdwProcessId);

    lpgui = new GUITHREADINFO();
    lpgui.cbSize = Marshal.SizeOf(lpgui);

    return GetGUIThreadInfo(lpdwProcessId, ref lpgui); //<!- error here, returns false
}

Answer 1

我认为您在调用 GetWindowThreadProcessId 时使用了错误的值, 如果您查看文档 here ，您将看到第二个参数是进程 ID(正如您命名的那样)，但线程 ID 位于返回值中。

所以换句话说，我认为你的代码应该是这样的(未经测试):

public static bool GetInfo(unit hwnd, out GUITHREADINFO lpgui)
{ 
    uint lpdwProcessId;
    uint threadId = GetWindowThreadProcessId(hwnd, out lpdwProcessId);

    lpgui = new GUITHREADINFO();
    lpgui.cbSize = Marshal.SizeOf(lpgui);

    return GetGUIThreadInfo(threadId, ref lpgui); 
}