GridView自定义分页，模仿GridView的自动分页功能

这个分页是自定义分页，只从数据库中读取当前的数据，样子看着跟GridView的自动分页基本上完全一样。

1、用两个ViewState保存当前页数CurrentPage和总行数RowCount

#region　分页
        /// <summary>
        /// 当前页
        /// </summary>
        private int CurrentPage
        {
            get
            {
                if (ViewState["CurrentPage"] == null)
                {
                    return 0; // 页数从０开始
                }
                else
                {
                    return (int)ViewState["CurrentPage"];
                }
            }
            set
            {
                ViewState["CurrentPage"] = value;
            }
        }

        /// <summary>
        /// 总行数
        /// </summary>
        private int RowCount
        {
            get
            {
                if (ViewState["RowCount"] == null)
                {
                    return 0;
                }
                else
                {
                    return (int)ViewState["RowCount"];
                }
            }
            set
            {
                ViewState["RowCount"] = value;
            }
        }
        #endregion

2、加载数据 

private void LoadData()
        {
            。。。。。。

            int totalCount = bll.GetRowcount(letter, teamName);// 总行数
            RowCount = totalCount;// 保存总行数到ViewState中

　　　　 // 得到当前页的数据，前两个参数分别是每页显示的记录数和当前是第几页

            List<StdTeamInfo> lstStdTeam = bll.GetListByPager(GridView1.PageSize, CurrentPage + 1, letter, teamName);
            GridView1.DataSource = lstStdTeam;
            GridView1.DataBind();
        }

3、加GridView的分页方法，跟自动分页时加分页方法一样

protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            this.CurrentPage = e.NewPageIndex;//保存当前是第几页到ViewState中
            LoadData();
        }

4、重写OnPreRender，加分页的链接 

protected override void OnPreRender(EventArgs e)
        {

　　　　// Utility.GetPagerString,此方法在第５步介绍，功能是得到分页的链接字符串
            string pagerString = Utility.GetPagerString(RowCount, (CurrentPage + 1), GridView1.PageSize, this.GridView1.ClientID);
            if (pagerString != "")
            {
                int index = this.GridView1.Rows.Count;
                GridViewRow rowHeader = new GridViewRow(index, index, DataControlRowType.Pager, DataControlRowState.Normal);
                TableCell headerCell = new TableCell();
                headerCell.ColumnSpan = 8;
                headerCell.Text = pagerString;
                rowHeader.Cells.Add(headerCell);
                this.GridView1.Controls[0].Controls.Add(rowHeader);
            }
        }

5、GetPagerString方法，得到分页的链接字符串

/// <summary>
        /// 返回分页的链接串
        /// </summary>
        /// <param name="totalCount">总行数</param>
        /// <param name="currentPage">当前第几页（从０开始）</param>
        /// <param name="pageSize">每页记录数</param>
        /// <param name="gridViewID">GridView控件ID</param>
        /// <returns></returns>
        public static string GetPagerString(int totalCount, int currentPage, int pageSize,
            string gridViewID)
        {
            gridViewID = gridViewID.Replace("_", "$"); 
            // 总页数
            int pageCount = (totalCount % pageSize == 0) ? (totalCount / pageSize) : (totalCount / pageSize + 1);
            if (pageCount == 1 || pageCount == 0) return "";

            int pageFrom = (currentPage - (currentPage % 30 == 0 ? 30 : currentPage % 30)) + 1; // 这里把显示的最大页面数设为了３０
            if (pageFrom < 0) pageFrom = 1;
            int pageTo = currentPage + (30 - (currentPage % 30 == 0 ? 30 : currentPage % 30));
            if (pageTo > pageCount) pageTo = pageCount;

            StringBuilder sb = new StringBuilder();
            sb.Append("<table border=\"0\"><tr>");
            if (currentPage > 30)
                sb.Append("<td><a href=\"javascript:__doPostBack('" + gridViewID + "','Page$" + (pageFrom - 1) + "')\">...</a></td>");
            for (int i = pageFrom; i <= pageTo; i++)
            {
                if (i == currentPage)
                    sb.Append("<td><span>" + i + "</span></td>");
                else
                    sb.Append("<td><a href=\"javascript:__doPostBack('" + gridViewID + "','Page$" + i + "')\">" + i + "</a></td>");
            }
            if (pageTo < pageCount)
                sb.Append("<td><a href=\"javascript:__doPostBack('" + gridViewID + "','Page$" + (pageTo + 1) + "')\">...</a></td>");

            sb.Append("<td>共" + pageCount + "页</td>");

            sb.Append("</tr></table>");

            return sb.ToString();
        }

至此这个自定义分页完成了。样式跟GridView的自定义分页一样，但是只读出需要的数据，页面显示速度快了不少。