你是做什么的时候，你不能使用ViewState的？

问题描述

我有一个相当复杂的页面，可以动态建立一个中继器内的用户控件。该中继器必须在初始化页面活动期间 ViewState中之前被绑定初始化或动态创建的用户控件将不保留其状态。

I have a rather complex page that dynamically builds user controls inside of a repeater. This repeater must be bound during the Init page event before ViewState is initialized or the dynamically created user controls will not retain their state.

这将创建一个有趣的第二十二条军规，因为我绑定中继器的需求对象在初始页面加载创建，然后坚持在内存中，直到用户选择离开或保存。

This creates an interesting Catch-22 because the object I bind the repeater to needs to be created on initial page load, and then persisted in memory until the user opts to leave or save.

由于我不能使用的ViewState 来存储这些对象，但有它初始化期间可用，我不得不将其存储在会话。

Because I cannot use ViewState to store this object, yet have it available during Init, I have been forced to store it in Session.

这也有问题，因为我必须明确地空以模拟如何的ViewState 工作在非回发会话值。

This also has issues, because I have to explicitly null the session value during non postbacks in order to emulate how ViewState works.

必须有一个更好的办法在这种情况下状态管理。任何想法？

There has to be a better way to state management in this scenario. Any ideas?

编辑：关于使用一些好的建议 LoadViewState ，但我仍然有不被状态恢复的问题时，我这样做

Some good suggestions about using LoadViewState, but I'm still having issues with state not being restored when I do that.

下面是有点如果页面结构

Here is somewhat if the page structure

首页 - >用户控件 - >转发器 - >动态地创建用户控件的施氮量

Page --> UserControl --> Repeater --> N amount of UserControls Dynamicly Created.

我把覆盖 LoadViewState 父用户控件，因为它的设计是完全封装和独立的页它是。我想知道如果这是问题的所在。

I put the overridden LoadViewState in the parent UserControl, as it is designed to be completely encapsulated and independent of the page it is on. I am wondering if that is where the problem is.

推荐答案

在页面上的LoadViewState方法是绝对的答案。这里的总体思路：

The LoadViewState method on the page is definitely the answer. Here's the general idea:

protected override void LoadViewState( object savedState ) {
  var savedStateArray = (object[])savedState;

  // Get repeaterData from view state before the normal view state restoration occurs.
  repeaterData = savedStateArray[ 0 ];

  // Bind your repeater control to repeaterData here.

  // Instruct ASP.NET to perform the normal restoration of view state.
  // This will restore state to your dynamically created controls.
  base.LoadViewState( savedStateArray[ 1 ] );
}

SaveViewState需要创建我们在上面使用savedState数组：

SaveViewState needs to create the savedState array that we are using above:

protected override object SaveViewState() {
  var stateToSave = new List<object> { repeaterData, base.SaveViewState() };
  return stateToSave.ToArray();
}

不要忘了也结合在初始化中继器或使用code这样的负荷：

Don't forget to also bind the repeater in Init or Load using code like this:

if( !IsPostBack ) {
  // Bind your repeater here.
}

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