保存的值，并从视图状态读 [英] Saving a value to and reading from the viewstate

问题描述

我不是太熟悉.NET，但我要救一个简单的值（1和1000之间的数字，这是一个特殊的高度 DIV ）的视图状态和检索它时，更新面板重新加载（无论是在某处标记或使用JavaScript）。什么是最简单的方法是什么？

I'm not too familiar with .NET, but I want to save a simple value (a number between 1 and 1000, which is the height of a particular div) to the viewstate and retrieve it when the update panel reloads (either in the markup somewhere or with javascript). What is the simplest way to do this?

此页面给我以下code：

string strColor;
if (Page.IsPostBack)
{
   // Retrieve and display the property value.
   strColor = (string)ViewState["color"];
   Response.Write(strColor);
}
else
   // Save the property value.
   ViewState["color"] = "yellow";

不过，我不是在哪里或如何访问例如strColor完全清楚。

However, I'm not totally clear on where or how to access the example strColor.

由于这是在code的后面，在那里将的Response.Write 吐甚至是code呢？我找不到它，当我尝试这个code。我如何使用JavaScript来设置值，而不是背后的code设置呢？

Since this is in the code behind, where will Response.Write even spit that code out? I couldn't find it when I tried this code. And how do I use javascript to set that value, instead of setting it in the code behind?

推荐答案

您可以简单地设置分区作为服务器控件像这样：

You can simply set the div as a server control as so:

<div id="yourdiv" runat="server" ...

而当页面回;只需设置它通过设置其属性的高度;例如：

And when the page posts back; simply set it's height by setting its attributes; for example:

yourDiv.Attributes("style","height:"+height_read_from_ViewState+"px;");

或者，你可以存储在客户端的高度，采用了隐藏字段，并读取隐藏字段的值在服务器端设置div的高度。

Or, you can store the height on the client side, using a Hidden field and reading that hidden field's value on the server side to set the div's height.

<asp:hiddenfield id="hdnHeight" runat="server" />

您在JavaScript设置的高度像这样：

You set the height in Javascript as so:

function setHeight(value)
{
  document.getElementById('<%=hdnHeight.ClientID').value=value;
}

和上回发服务器端：

yourDiv.Attributes("style","height:"+hdnHeight.Value+"px;");

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