自定义控件继承datalist的问题

Question

嗨，大家好：
我在网上down了个模仿petshop4.0中customlist的自定义控件，继承了datalist。
生成没有错误。但是在页面中使用的时候，在<itemtemplate>中无法添加任何东西，包括空格如果有了就会报错--“呈现该控件时出错，请检查并确保所有属性都有效。”如果<itemtemplate>中没有任何东西是没有错的。
百思不得其解。
望高人指点。
下面是该控件的代码。基本就是petshop中的customlist的代码，就修改了几处。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 Control
{
    public class CustomList :DataList{
        //Static constants
        private string HTML1 = "<table cellpadding=0 cellspacing=0 ><tr><td colspan=13>";
        protected const string HTML2 = "</td></tr><tr>";
        protected const string HTML4 = "</tr></table>";
        private static readonly Regex RX = new Regex(@"^&page=d+", RegexOptions.Compiled);
        private const string LINK_PREV = "<td><a href=?page={0}>&nbsp;上一页</a></td>";
        private const string LINK_MORE = "<td><a href=?page={0}>下一页&nbsp;</a></td>";
        private const string LINK_DISPLAY = "<td><a href=?page={0}>&nbsp;{1}&nbsp;</a></td>";
        private const string KEY_PAGE = "page";
        private const string COMMA = "?";
        private const string AMP = "&";
       
        protected string emptyText;
        private IList dataSource;
        private int pageSize = 10;
        private int currentPageIndex;
        private int itemCount;
         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;
                }
            }
        }        public int PageSize {
            get { return pageSize; }
            set { pageSize = value; }
        }        protected int PageCount {
            get { return (ItemCount - 1) / pageSize; }
        }        virtual protected int ItemCount {
            get { return itemCount; }
            set { itemCount = value; }
        }        virtual public int CurrentPageIndex {
            get { return currentPageIndex; }
            set { currentPageIndex = value; }
        }        public string EmptyText {
            set { emptyText = value; }
        }        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)-1 : 0;
                SetPage(index);
            }
        }
        /**//// <summary>
        /// Overriden method to control how the page is rendered
        /// </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
            string query = Context.Request.Url.Query.Replace(COMMA, AMP);
            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);            //列表信息
            writer.Write("<td>共&nbsp;" + PageCount + "&nbsp;页&nbsp;" + itemCount + "&nbsp项</td>");
            //导航到上一页
            if (currentPageIndex > 0)
                writer.Write(string.Format(LINK_PREV, (currentPageIndex ) + query));
            else
            {
                writer.Write("<td>&nbsp;上一页&nbsp;</td>");
            }            //得到页码导航
            for (int i =0; i <= 9 && i <= PageCount && (currentPageIndex - currentPageIndex % 10 + i)<=PageCount ; i++)
                {
                    if (currentPageIndex - currentPageIndex % 10 + i == currentPageIndex)
                    {
                        writer.Write("<td>&nbsp;" + (currentPageIndex+1) + "&nbsp;</td>");
                    }
                    else
                    {
                        writer.Write(string.Format(LINK_DISPLAY, (currentPageIndex - currentPageIndex % 10 + i+1) + query,(currentPageIndex - currentPageIndex % 10 + i+1) ));                    }
                }
           
            //导航到下一页
            if (currentPageIndex < PageCount)
                writer.Write(string.Format(LINK_MORE, (currentPageIndex + 2) + query));
            else
            {
                writer.Write("<td>&nbsp;下一页&nbsp;</td>");
            }            //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);        }        public event DataGridPageChangedEventHandler PageIndexChanged;        virtual protected void OnPageIndexChanged(DataGridPageChangedEventArgs e) {
            if (PageIndexChanged != null)
                PageIndexChanged(this, e);
        }
    }}

Answer 1

同样问题，哪位大大帮帮忙吧