/// <summary>
        /// 分页的实现(将DataSet中的数据分页显示)
        /// </summary>
        /// <param name="ds"></param>
        /// <returns></returns>
        public DataSet SplitDataSet()
        {
            DataSet ds = LoadData();
            DataSet vds = new DataSet();
            if (ds != null && ds.Tables[0].Rows.Count > 0)
            {
                vds = ds.Clone();
                int pageSize = PageSize;//每页显示的数据个数
                int pageIndex = PageIndex;//显示已分页的数据的页面页码
                int fromIndex = pageSize * (pageIndex - 1);
                int toIndex = pageSize * pageIndex - 1;


                //如果新显示页的数据下标不在查询到的数据范围内就重置页码
                if (toIndex > ds.Tables[0].Rows.Count - 1)
                {
                    if (fromIndex < ds.Tables[0].Rows.Count)
                    {
                        toIndex = ds.Tables[0].Rows.Count;
                    }
                    else
                    {
                        PageIndex = 1;
                        pageSize = PageSize;
                        pageIndex = PageIndex;
                        fromIndex = pageSize * (pageIndex - 1);
                        toIndex = pageSize * pageIndex - 1;
                    }
                }
                for (int i = fromIndex; i <= toIndex; i++)
                {
                    if (i >= ds.Tables[0].Rows.Count)
                        break;
                    vds.Tables[0].ImportRow(ds.Tables[0].Rows[i]);
                }
                ds.Dispose();
                DisplayCount = vds.Tables[0].Rows.Count;
            }
            return vds;
        }