C#用API如何遍历所有窗口句柄

//用来遍历所有窗口
        [DllImport("user32.dll")]
        private static extern bool EnumWindows(WNDENUMPROC lpEnumFunc, int lParam);

//获取窗口Text
        [DllImport("user32.dll")]
        private static extern int GetWindowTextW(IntPtr hWnd, [MarshalAs(UnmanagedType.LPWStr)]StringBuilder lpString, int nMaxCount);

//获取窗口类名
        [DllImport("user32.dll")]
        private static extern int GetClassNameW(IntPtr hWnd, [MarshalAs(UnmanagedType.LPWStr)]StringBuilder lpString, int nMaxCount);

　　　　
        public struct WindowInfo　　　　//自定义一个类，用来保存句柄信息，有遍历的时候，随便也用空上句柄来获取些信息，呵呵
        {
            public IntPtr hWnd;
            public string szWindowName;
            public string szClassName;
        }

        public WindowInfo[] GetAllDesktopWindows()
        {
            List<WindowInfo> wndList = new List<WindowInfo>();

            //enum all desktop windows
            EnumWindows(delegate(IntPtr hWnd, int lParam)
            {
                WindowInfo wnd = new WindowInfo();
                StringBuilder sb = new StringBuilder(256);
                //get hwnd
                wnd.hWnd = hWnd;
                //get window name 
                (hWnd, sb, sb.Capacity);
                wnd.szWindowName = sb.ToString();
                //get window class
                GetClassNameW(hWnd, sb, sb.Capacity);
                wnd.szClassName = sb.ToString();
                //add it into list
                wndList.Add(wnd);
                return true;
            }, 0);

            return wndList.ToArray();
        }