详细代码如下,慢慢体会..
using System;using System.Collections;using System.Collections.Specialized;using System.Text;using System.Text.RegularExpressions;using System.Web.UI;using System.Web.UI.WebControls;namespace CustomControl
{
/// <summary>
/// CustomList 的摘要说明 /// 重构DataList控件
/// </summary> public class CustomList : DataList { //静态常量 protected const string HTML1 = "<table width=100% cellpadding=0 cellspacing=0><tbody><tr><td>"; protected const string HTML2 = "</td></tr><tr><td align=right>"; //protected const string HTML3 = "</td><td align=center class=paging>"; //protected const string HTML5 = "</td><td align=right class=paging>"; protected const string HTML4 = "</td></tr></tbody></table>"; private static readonly Regex RX = new Regex(@"^&page=\d+", RegexOptions.Compiled); private const string LINK_PREV = "<a href=?page={0}>前一页</a>"; private const string LINK_MORE = "<a href=?page={0}>下一页</a>"; private const string LINK_FIRST = "<a href=?page={0}>首页</a>"; //首页 private const string LINK_LAST = "<a href=?page={0}>尾页</a>"; //尾页 private const string KEY_PAGE = "page"; private const string COMMA = "?"; private const string AMP = "&"; protected string emptyText; private IList dataSource; //数据源 private int pageSize = 10; //每页大小 private int currentPageIndex; //当前页 private int itemCount; //数据条目总数 /// <summary> /// 指定要绑定的数据源 /// </summary> override public object DataSource { set { //This try catch block is to avoid issues with the VS.NET designer //The designer will try and bind a datasource which does not derive from ILIST try { dataSource = (IList)value; ItemCount = dataSource.Count; } catch { dataSource = null; ItemCount = 0; } } } /// <summary> /// 每页大小 /// </summary> public int PageSize { get { return pageSize; } set { pageSize = value; } } /// <summary> /// 总页数 /// </summary> protected int PageCount { get { return (ItemCount - 1) / pageSize; } } /// <summary> /// 可重载,数据条目总数 /// </summary> virtual protected int ItemCount { get { return itemCount; } set { itemCount = value; } } /// <summary> /// 可重载,当前页码 /// </summary> virtual public int CurrentPageIndex { get { return currentPageIndex; } set { currentPageIndex = value; } } /// <summary> /// 空Text /// </summary> public string EmptyText { set { emptyText = value; } } /// <summary> /// 设置页面,翻页事件 /// </summary> /// <param name="index"></param> public void SetPage(int index) { OnPageIndexChanged(new DataGridPageChangedEventArgs(null, index)); } override protected void OnLoad(EventArgs e) { if (Visible) { string page = Context.Request[KEY_PAGE]; int index = (page != null) ? int.Parse(page) : 0; SetPage(index); } } /// <summary> /// Overriden method to control how the page is rendered /// Render提交写入 /// </summary> /// <param name="writer"></param> override protected void Render(HtmlTextWriter writer) { //Check there is some data attached if (ItemCount == 0) { writer.Write(emptyText); return; } //Mask the query "?"/"&"二个符号 string query = Context.Request.Url.Query.Replace(COMMA, AMP); //正则表达式替换 query = RX.Replace(query, string.Empty); // Write out the first part of the control, the table header writer.Write(HTML1); // Call the inherited method base.Render(writer); // Write out a table row closure writer.Write(HTML2); if (currentPageIndex > 0) writer.Write(string.Format(LINK_FIRST, 0 + query) + " "); //首页 //Determin whether next and previous buttons are required //Previous button? if (currentPageIndex > 0) writer.Write(string.Format(LINK_PREV, (currentPageIndex - 1) + query)); //Close the table data tag //writer.Write(HTML3); //当前页/总页数 writer.Write(" " + string.Format("页码:{0}/{1}", currentPageIndex + 1, PageCount + 1) + " "); //writer.Write(HTML5); //Next button? if (currentPageIndex < PageCount) writer.Write(string.Format(LINK_MORE, (currentPageIndex + 1) + query)); if (currentPageIndex < PageCount) writer.Write(" " + string.Format(LINK_LAST, PageCount + query)); //尾页 //Close the table writer.Write(HTML4); } override protected void OnDataBinding(EventArgs e) { //Work out which items we want to render to the page int start = CurrentPageIndex * pageSize; int size = Math.Min(pageSize, ItemCount - start); IList page = new ArrayList(); //Add the relevant items from the datasource for (int i = 0; i < size; i++) page.Add(dataSource[start + i]); //set the base objects datasource base.DataSource = page; base.OnDataBinding(e); } /// <summary> /// 翻页事件 /// </summary> public event DataGridPageChangedEventHandler PageIndexChanged; /// <summary> /// 可重载,翻页事件处理 /// </summary> /// <param name="e"></param> virtual protected void OnPageIndexChanged(DataGridPageChangedEventArgs e) { if (PageIndexChanged != null) PageIndexChanged(this, e); } }
}