c# api 模拟按钮点击问题，高手请进！
[DllImport("user32", EntryPoint = "SetParent", ExactSpelling = true, CharSet = CharSet.Ansi, SetLastError = true)]
  public static extern int SetParent(IntPtr hWndChild, IntPtr hWndNewParent);
  [DllImport("user32.dll", EntryPoint = "FindWindowEx")]
  private static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
  [DllImport("user32", EntryPoint = "FindWindowA", ExactSpelling = true, CharSet = CharSet.Ansi, SetLastError = true)]
  public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
  [DllImport("user32.dll", EntryPoint = "SendMessageA", ExactSpelling = true, CharSet = CharSet.Ansi, SetLastError = true)]
  private static extern int SendMessage(int hwnd, int wMsg, int wParam, int lParam);
  [DllImport("User32.dll", EntryPoint = "SendMessage")]
  private static extern int SendMessage(IntPtr hWnd,int Msg, IntPtr wParam, string lParam); 
  private const int WM_GETTEXT = 0x000D;
  private const int WM_SETTEXT = 0x000C;
  private const int WM_CLICK = 0x00F5;
  [DllImport("shell32.dll", EntryPoint = "ShellExecuteA", ExactSpelling = true, CharSet = CharSet.Ansi, SetLastError = true)]
  private static extern int ShellExecute(int hwnd, string lpOperation, string lpFile, string lpParameters, string lpDirectory, int nShowCmd);
  private const int WM_SYSCOMMAND = 0x112;
  private const int SC_MAXIMIZE = 0xF030;
  private const int SC_MINIMIZE = 0xF020;
  private const int SC_RESTORE = 0xF120;
  public const int SW_HIDE = 0;
  public const int SW_SHOW = 5;
  [DllImport("user32.dll ", ExactSpelling = true, CharSet = CharSet.Ansi, SetLastError = true)]
  private static extern int ShowWindow(int hwnd, int nCmdShow);

  private void timer1_Tick(object sender, EventArgs e)
  {
  IntPtr h = FindWindow("#32770", "东北证券通达信V6.03");
  SetParent(h, this.panel1.Handle); //嵌套到panel1内
  SendMessage(h.ToInt32(), WM_SYSCOMMAND, SC_MAXIMIZE, 0);
  ShowWindow(h.ToInt32(), SW_SHOW);
  timer1.Enabled = false;
  //得到控件
  IntPtr MIMA = new IntPtr(0);
  IntPtr YZMA = new IntPtr(0);
  IntPtr DL = new IntPtr(0);
  if (!h.Equals(IntPtr.Zero))
  {
  //得到控件子窗体，并设置其内容 
  MIMA = FindWindowEx(h, MIMA, "SafeEdit", null);
  if (!MIMA.Equals(IntPtr.Zero))
  {
  //调用SendMessage方法设置其内容 
  SendMessage(MIMA, WM_SETTEXT, h, "123456");

  }
  YZMA = FindWindowEx(h, MIMA, "SafeEdit", null);
  if (!YZMA.Equals(IntPtr.Zero))
  {
  //调用SendMessage方法设置其内容 
  SendMessage(YZMA, WM_SETTEXT, h, "123456");

  }
  //按钮点击
  DL = FindWindowEx(h, DL, "AfxWnd42", null);

  if (!DL.Equals(IntPtr.Zero))
  {
  SendMessage(DL, WM_CLICK, h, "0");