页面恢复

1 using System;
2   using System.Web;
3 using System.Web.SessionState;
4 using System.Web.UI;
5 namespace GentleSoft.MyOffice
6 {
7 /// <summary>
8 /// 页面状态持久化。可保存和恢复页面的ViewState和表单内容
9 /// </summary>
10 public class PersistencePage : GentleUtil.Page.Page
11 {
12
13 /// <summary>
14 /// 是否从Session中恢复状态（此值来控制LoadPageStateFromPersistenceMedium的取值规则以及回发事件RaisePostBackEvent执行与否，防止状态恢复时重复执行控件事件）
15 /// </summary>
16 private bool taoist_IsLoadPageStateFromToSession = false ;
17
18 /// <summary>
19 /// 页面状态保存到的Session
20 /// </summary>
21 private string taoist_PageStateSession = "" ;
22
23 /// <summary>
24 /// 保存页面状态（包括ViewState和表单内容）
25 /// </summary>
26 /// <param name="sessionName"> 存储页面状态的session </param>
27 protected void SavePageStateToSession( string sessionName)
28 {
29
30 this .taoist_PageStateSession = sessionName;
31 object state = base .LoadPageStateFromPersistenceMedium();
32
33 // 保存ViewState与表单内容
34 Pair ps = new Pair();
35 ps.First = state;
36 ps.Second = base .DeterminePostBackMode();
37 Session[sessionName] = ps;
38 }
39
40 /// <summary>
41 /// 重写此方法，如果是从Session中恢复状态则无需触发控件事件
42 /// </summary>
43 /// <param name="sourceControl"></param>
44 /// <param name="eventArgument"></param>
45 protected override void RaisePostBackEvent(IPostBackEventHandler sourceControl, string eventArgument)
46 {
47 if ( ! taoist_IsLoadPageStateFromToSession)
48 {
49 base .RaisePostBackEvent(sourceControl, eventArgument);
50 }
51 }
52
53 /// <summary>
54 /// 重写此方法，只有taoist_IsLoadPageStateFromToSession为true时才从Session中还原ViewState。
55 /// </summary>
56 /// <returns></returns>
57 protected override object LoadPageStateFromPersistenceMedium()
58 {
59 object state;
60
61 if (taoist_IsLoadPageStateFromToSession)
62 {
63 // 还原ViewState
64 Pair ps = (Pair)Session[taoist_PageStateSession];
65 state = ps.First;
66 // 清空当前Session，保证只能恢复一次，防止无效恢复
67 Session[taoist_PageStateSession] = null ;
68 }
69 else
70 state = base .LoadPageStateFromPersistenceMedium();
71
72 return state;
73 }
74
75 /// <summary>
76 /// 重载此方法，增加表单恢复，并设置是否恢复Session
77 /// </summary>
78 /// <returns></returns>
79 protected override System.Collections.Specialized.NameValueCollection DeterminePostBackMode()
80 {
81
82 System.Collections.Specialized.NameValueCollection formContent = base .DeterminePostBackMode();
83
84 if (formContent == null )
85 {
86 // 判断是否返回
87 if (Request.QueryString[ " taoist_PageStateSession " ] != null )
88 {
89 taoist_PageStateSession = Convert.ToString(Request.QueryString[ " taoist_PageStateSession " ]);
90 if (Session[taoist_PageStateSession] != null && ! taoist_PageStateSession.Equals( "" ))
91 {
92 // 设置需要还原ViewState
93 this .taoist_IsLoadPageStateFromToSession = true ;
94
95 // 先还原表单
96 Pair ps = Session[taoist_PageStateSession] as Pair;
97 if (ps != null )
98 {
99 formContent = ps.Second as System.Collections.Specialized.NameValueCollection;
100 }
101 }
102
103 }
104 else
105 {
106 Session[ " mypagestate " ] = null ;
107 }
108 }
109
110 return formContent;
111 }
112
113 }
114 }