群里人问的消息切换分页问题，我就标记一下

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Text;
 
namespace Text
{
    public class Program
    {
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        static extern UInt32 SendMessage(IntPtr hWnd, UInt32 Msg, UInt32 wParam, UInt32 lParam);
 
        public const UInt32 TCM_FIRST = 0x1300;
        public const UInt32 TCM_GETIMAGELIST = (TCM_FIRST + 2);
        public const UInt32 TCM_SETIMAGELIST = (TCM_FIRST + 3);
        public const UInt32 TCM_GETITEMCOUNT = (TCM_FIRST + 4);
        public const UInt32 TCM_GETITEMA = (TCM_FIRST + 5);
        public const UInt32 TCM_GETITEMW = (TCM_FIRST + 60);
        public const UInt32 TCM_SETITEMA = (TCM_FIRST + 6);
        public const UInt32 TCM_SETITEMW = (TCM_FIRST + 61);
        public const UInt32 TCM_INSERTITEMA = (TCM_FIRST + 7);
        public const UInt32 TCM_INSERTITEMW = (TCM_FIRST + 62);
        public const UInt32 TCM_DELETEITEM = (TCM_FIRST + 8);
        public const UInt32 TCM_DELETEALLITEMS = (TCM_FIRST + 9);
        public const UInt32 TCM_GETITEMRECT = (TCM_FIRST + 10);
        public const UInt32 TCM_GETCURSEL = (TCM_FIRST + 11);
        public const UInt32 TCM_SETCURSEL = (TCM_FIRST + 12);
        public const UInt32 TCM_HITTEST = (TCM_FIRST + 13);
        public const UInt32 TCM_SETITEMEXTRA = (TCM_FIRST + 14);
        public const UInt32 TCM_ADJUSTRECT = (TCM_FIRST + 40);
        public const UInt32 TCM_SETITEMSIZE = (TCM_FIRST + 41);
        public const UInt32 TCM_REMOVEIMAGE = (TCM_FIRST + 42);
        public const UInt32 TCM_SETPADDING = (TCM_FIRST + 43);
        public const UInt32 TCM_GETROWCOUNT = (TCM_FIRST + 44);
        public const UInt32 TCM_GETCURFOCUS = (TCM_FIRST + 47);
        public const UInt32 TCM_SETCURFOCUS = (TCM_FIRST + 48);
        public const UInt32 TCM_SETMINTABWIDTH = (TCM_FIRST + 49);
        public const UInt32 TCM_DESELECTALL = (TCM_FIRST + 50);
        public const UInt32 TCM_HIGHLIGHTITEM = (TCM_FIRST + 51);
        public const UInt32 TCM_SETEXTENDEDSTYLE = (TCM_FIRST + 52); // optional wParam == mask
        public const UInt32 TCM_GETEXTENDEDSTYLE = (TCM_FIRST + 53);
 
        static void Main(string[] args)
        {
            IntPtr h = new IntPtr(句柄自己取);
            UInt32 count = SendMessage(h, TCM_GETITEMCOUNT, 0, 0);
            Console.WriteLine("共有 " + count + " 个分页");
 
            UInt32 index = SendMessage(h, TCM_GETCURSEL, 0, 0);
            Console.WriteLine("当前选中第 " + (index + 1) + " 页");
 
            if (index == 0)
            {
                index = count - 1;
            }
            else
            {
                index = 0;
            }
 
            SendMessage(h, TCM_SETCURSEL, index, 0);
            Console.WriteLine("已跳转到 " + (index + 1) + " 页");
 
            Console.ReadKey();
        }
    }
}

 如题，获取到tabcontrol控件句柄后使用
SendMessage(hTab,TCM_SETCURFOCUS,1,0);//这句话是相当重要的，不然的话tab子窗口不会跟随切换。就这一句话，搞了很久。
SendMessage(hTab,TCM_SETCURSEL,2,0);//想切换的的tab控件的第二个索引项
验证无效，烦请各位大大帮看下问题出在哪里？