ASP.net ListItem Attributes 属性回传丢失的解决方案

该方法为网上整理

1. 新继承一个列表控件

  新控件中重写两个方法：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI.WebControls;

namespace GetDateDome
{
    public class ListBoxEx:ListBox
    {
        protected override object SaveViewState()
        {
            // create object array for Item count + 1
            object[] allStates = new object[this.Items.Count + 1];

            // the +1 is to hold the base info
            object baseState = base.SaveViewState();
            allStates[0] = baseState;

            Int32 i = 1;
            // now loop through and save each Style attribute for the List
            foreach (ListItem li in this.Items)
            {
                Int32 j = 0;
                string[][] attributes = new string[li.Attributes.Count][];
                foreach (string attribute in li.Attributes.Keys)
                {
                    attributes[j++] = new string[] { attribute, li.Attributes[attribute] };
                }
                allStates[i++] = attributes;
            }
            return allStates;
        }

        protected override void LoadViewState(object savedState)
        {
            if (savedState != null)
            {
                object[] myState = (object[])savedState;

                // restore base first
                if (myState[0] != null)
                    base.LoadViewState(myState[0]);

                Int32 i = 1;
                foreach (ListItem li in this.Items)
                {
                    // loop through and restore each style attribute
                    foreach (string[] attribute in (string[][])myState[i++])
                    {
                        li.Attributes[attribute[0]] = attribute[1];
                    }
                }
            }
        }

    }
}

 2  页面注册控件

<%@ Register assembly="GetDateDome" namespace="GetDateDome" tagprefix="my" %>

3 使用新控件

 <my:ListBoxEx ID="lstUnselectCol" runat="server" Style=" 100%;height:100%;" ></my:ListBoxEx>

            //设置属性 
            ListItem p = new ListItem(i["Item"].ToString(), i["value"].ToString());
            p.Attributes.Add("type", i["type"].ToString());
            lstUnselectCol.Items.Add(p);


            //获取属性
            string msg = srcList.SelectedItem.Attributes["type"];

 4 最后记着设置 EnableViewState="true"