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：

1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Web;
 5 using System.Web.UI.WebControls;
 6 
 7 namespace GetDateDome
 8 {
 9     public class ListBoxEx:ListBox
10     {
11         protected override object SaveViewState()
12         {
13             // create object array for Item count + 1
14             object[] allStates = new object[this.Items.Count + 1];
15 
16             // the +1 is to hold the base info
17             object baseState = base.SaveViewState();
18             allStates[0] = baseState;
19 
20             Int32 i = 1;
21             // now loop through and save each Style attribute for the List
22             foreach (ListItem li in this.Items)
23             {
24                 Int32 j = 0;
25                 string[][] attributes = new string[li.Attributes.Count][];
26                 foreach (string attribute in li.Attributes.Keys)
27                 {
28                     attributes[j++] = new string[] { attribute, li.Attributes[attribute] };
29                 }
30                 allStates[i++] = attributes;
31             }
32             return allStates;
33         }
34 
35         protected override void LoadViewState(object savedState)
36         {
37             if (savedState != null)
38             {
39                 object[] myState = (object[])savedState;
40 
41                 // restore base first
42                 if (myState[0] != null)
43                     base.LoadViewState(myState[0]);
44 
45                 Int32 i = 1;
46                 foreach (ListItem li in this.Items)
47                 {
48                     // loop through and restore each style attribute
49                     foreach (string[] attribute in (string[][])myState[i++])
50                     {
51                         li.Attributes[attribute[0]] = attribute[1];
52                     }
53                 }
54             }
55         }
56 
57     }
58 }      

 2  页面注册控件

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

3 使用新控件

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

1             //设置属性 
2             ListItem p = new ListItem(i["Item"].ToString(), i["value"].ToString());
3             p.Attributes.Add("type", i["type"].ToString());
4             lstUnselectCol.Items.Add(p);
5 
6 
7             //获取属性
8             string msg = srcList.SelectedItem.Attributes["type"];      

 4 最后记着设置 EnableViewState="true"

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[转载请保留作者信息  作者：冯天文 ]