获取一个窗体上EDit中的文字(基于user32.dll的控件句柄实现)

【实例截图】

【核心代码】

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

        [DllImport("user32.dll", EntryPoint = "FindWindowEx", SetLastError = true)]
        public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);

        [DllImport("user32.dll", EntryPoint = "SendMessage", SetLastError = true, CharSet = CharSet.Auto)]
        public static extern int SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, IntPtr lParam);

        [DllImport("user32.dll", EntryPoint = "SendMessageA")]
        public static extern int SendMessageA(IntPtr hwnd, int wMsg, int wParam, Byte[] lParam);

        [DllImport("user32.dll", EntryPoint = "SetForegroundWindow", SetLastError = true)]
        public static extern void SetForegroundWindow(IntPtr hwnd);

        [DllImport("user32.dll")]
        public static extern int EnumChildWindows(IntPtr hWndParent, CallBack lpfn, int lParam);

        public delegate bool CallBack(IntPtr hwnd, int lParam);

        const int WM_GETTEXT = 0x000D;

        const int buffer_size = 1024;
        //StringBuilder buffer = new StringBuilder(buffer_size);
        byte[] buffer = new byte[buffer_size];
        public Form1()
        {
            InitializeComponent();
        }

        public static List<IntPtr> GetIntPtr(IntPtr hwd)
        {
            List<IntPtr> listIntPtr = new List<IntPtr>();
            EnumChildWindows(hwd, delegate(IntPtr hWnd, int lParam)
            {
                listIntPtr.Add(hWnd);
                return true;
            }, 0);
            return listIntPtr;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //获取窗口句柄
            IntPtr intptr = FindWindow(null, "FormComTest");

            //获取窗口所有控件句柄
            List<IntPtr> list = GetIntPtr(intptr);

            //获取文本框内容
            IntPtr temp = (IntPtr)0x001413A8;
            //SendMessageA(temp, WM_GETTEXT, buffer_size, buffer);
            //SendMessageA(temp, WM_GETTEXT, buffer_size, buffer);
            SendMessageA((IntPtr)list[1], WM_GETTEXT, buffer_size, buffer);
            textBox1.Text = System.Text.Encoding.Default.GetString(buffer);
        }