如何找不到"是"按钮的句柄

       dim WindowsTitleText as string = "Internet Explorer 脚本错误"
       MsgH = FindWindow(Nothing, WindowsTitleText)   '这里能找到对话框的句柄

      '我想找到上图中:"是"按钮的句柄,然后通过 PostMessage去点击它

        '下边我是期望找到:按扭的句柄,几种方法结果都是0
         Dim StaticH As Integer = FindWindowEx(MsgH, Nothing, "Static", Nothing)
       '  StaticH = FindWindowEx(MsgH, Nothing, "Button", Nothing)
        'Dim StaticH3 As Int32 = FindWindowEx(MsgH, 0, "Static", "是(&Y)")