[转载]C#获取进程的主窗口句柄

public class User32API

{

    private static Hashtable processWnd = null;



    public delegate bool WNDENUMPROC(IntPtr hwnd, uint lParam);



    static User32API()

    {

        if (processWnd == null)

        {

            processWnd = new Hashtable();

        }

    }



    [DllImport("user32.dll", EntryPoint = "EnumWindows", SetLastError = true)]

    public static extern bool EnumWindows(WNDENUMPROC lpEnumFunc, uint lParam);



    [DllImport("user32.dll", EntryPoint = "GetParent", SetLastError = true)]

    public static extern IntPtr GetParent(IntPtr hWnd);



    [DllImport("user32.dll", EntryPoint = "GetWindowThreadProcessId")]

    public static extern uint GetWindowThreadProcessId(IntPtr hWnd, ref uint lpdwProcessId);



    [DllImport("user32.dll", EntryPoint = "IsWindow")]

    public static extern bool IsWindow(IntPtr hWnd);



    [DllImport("kernel32.dll", EntryPoint = "SetLastError")]

    public static extern void SetLastError(uint dwErrCode);



    public static IntPtr GetCurrentWindowHandle()

    {

        IntPtr ptrWnd = IntPtr.Zero;

        uint uiPid = (uint)Process.GetCurrentProcess().Id;  // 当前进程 ID

        object objWnd = processWnd[uiPid];



        if (objWnd != null)

        {

            ptrWnd = (IntPtr)objWnd;

            if (ptrWnd != IntPtr.Zero && IsWindow(ptrWnd))  // 从缓存中获取句柄

            {

                return ptrWnd;

            }

            else

            {

                ptrWnd = IntPtr.Zero;

            }

        }



        bool bResult = EnumWindows(new WNDENUMPROC(EnumWindowsProc), uiPid);

        // 枚举窗口返回 false 并且没有错误号时表明获取成功

        if (!bResult && Marshal.GetLastWin32Error() == 0)

        {

            objWnd = processWnd[uiPid];

            if (objWnd != null)

            {

                ptrWnd = (IntPtr)objWnd;

            }

        }



        return ptrWnd;

    }



    private static bool EnumWindowsProc(IntPtr hwnd, uint lParam)

    {

        uint uiPid = 0;



        if (GetParent(hwnd) == IntPtr.Zero)

        {

            GetWindowThreadProcessId(hwnd, ref uiPid);

            if (uiPid == lParam)    // 找到进程对应的主窗口句柄

            {

                processWnd[uiPid] = hwnd;   // 把句柄缓存起来

                SetLastError(0);    // 设置无错误

                return false;   // 返回 false 以终止枚举窗口

            }

        }



        return true;

    }

}

调用User32API.GetCurrentWindowHandle()即可返回当前进程的主窗口句柄，如果获取失败则返回IntPtr.Zero。

http://www.cnblogs.com/qiuyi21/articles/1302732.html