ASP中列号ID无效，数据库中有ID字段

代码如下：
       private void Bind_rptList(int Topage)
        {
            int CurrentPage= Topage;
            int PageSize = 5;
            int PageCount;
            int RecordCount;
            string PageSQL;
            String DataTable = "Contents";
            string  DataField =" ID";
    //        string DataFields = "ID,UserName,Face,Sex,Ip,QQ,HomePage,Email,IsHidden,AddTime,IsReplyed,ReplyTime,ReplyContent";
            string DataOrders = "ID Desc";
            SqlConnection conn = GuestBook.CreateConnection();
            conn.Open();
            SqlCommand cmd = new SqlCommand("Select Count("+DataField+")From"+DataTable,conn);
            RecordCount = Convert.ToInt32(cmd.ExecuteScalar());//此行标明ID无效
            if ((RecordCount % PageSize) != 0)
            {
                PageCount = RecordCount / PageSize + 1;            }
            else {
                PageCount = RecordCount / PageSize;
            
            }
            if (Topage > PageCount)
            {
                CurrentPage = PageCount;
            }
            if (CurrentPage <= 1)
            {
                PageSQL = "Select Top" + PageSize + "" + DataField + "From" + DataTable + "Order By" + DataOrders;
            }
            else {
                PageSQL = "Select Top" + PageSize + "" + DataField + "From" + DataTable + "Where" + DataField + "Not in(Select Top"+ PageSize*(CurrentPage-1) +""+ DataField +"From" + DataTable + "Order By" + DataOrders+") Order By"+DataOrders;
            }