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 + ];

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

             Int32 i = ;
             // now loop through and save each Style attribute for the List
             foreach (ListItem li in this.Items)
             {
                 Int32 j = ;
                 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[] != null)
                     base.LoadViewState(myState[]);

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

     }
 }

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="width: 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"