DataList中的分页中首页、下一页、上一页、末页功能 如何写

using System; 
 using System.Collections; 
 using System.Configuration; 
 using System.Data; 
 using System.Linq; 
 using System.Web; 
 using System.Web.Security; 
 using System.Web.UI; 
 using System.Web.UI.HtmlControls; 
 using System.Web.UI.WebControls; 
 using System.Web.UI.WebControls.WebParts; 
 using System.Xml.Linq; 
 using System.Text; 

 namespace B2B.UC 
 { 
   public partial class UCPaged : System.Web.UI.UserControl 
   { 
     #region 属性组 
     ///  <summary> 
     /// 源数据源 
     ///  </summary> 
     private ArrayList objAL; 
     public ArrayList ObjAL 
     { 
       get { return objAL; } 
       set { objAL = value; } 
     } 

     ///  <summary> 
     /// 源数据控件 
     ///  </summary> 
     private DataList objDl; 
     public DataList ObjDl 
     { 
       get { return objDl; } 
       set { objDl = value; } 
     } 

     ///  <summary> 
     /// 源页面 
     ///  </summary> 
     private string pageName; 
     public string PageName 
     { 
       get { return pageName; } 
       set { pageName = value; } 
     } 

     ///  <summary> 
     /// url参数哈希表 
     ///  </summary> 
     private Hashtable parmHt; 
     public Hashtable ParmHt 
     { 
       get { return parmHt; } 
       set { parmHt = value; } 
     } 

     ///  <summary> 
     /// 每页显示数 
     ///  </summary> 
     private int pageSize; 
     public int PageSize 
     { 
       get 
       { 
         if (pageSize == null && pageSize  <= 0) 
         { 
           return 10; 
         } 
         else 
         { 
           return pageSize; 
         } 
       } 
       set { pageSize = value; } 
     } 
     #endregion 

     protected void Page_Load(object sender, EventArgs e) 
     { 
       bindPagedData(objAL, objDl); 
     } 

     ///  <summary> 
     /// 获得分页url参数和源页面 
     ///  </summary> 
     ///  <param name="sourceHT"> </param> 
     ///  <returns> </returns> 
     private StringBuilder getParmHT(Hashtable sourceHT) 
     { 
       StringBuilder parmStr = new StringBuilder(); 
       parmStr = parmStr.Append(pageName); 
       parmStr = parmStr.Append("?"); 
       if (sourceHT != null && sourceHT.Count > 0) 
       { 
         foreach (DictionaryEntry de in sourceHT) 
         {