July 2010
Beginner
552 pages
10h 14m
English
View state is used to preserve the state of controls on a Web Form across postbacks. In this lesson I show you how view state is stored on a web page, why it is useful, and how to turn it off.
This is the code for a simple web page that has only one server control on it:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Label.aspx.cs"
Inherits="Lesson10a.Label" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Label ID="Label1" runat="server" Text="Label" />
</div>
</form>
</body>
</html>When the preceding page is rendered on a browser, this is the HTML source for the page:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>
</title></head><body>
<form method="post" action="Label.aspx" id="form1">
<div class="aspNetHidden">
<input type="hidden" name="__VIEWSTATE" id="__viewstate"
value="/wEPDwUJOTczNTMyNjI5ZGTL47vwelS4H7Q78eBnfVHkSleBV1ii753zaCBSWQAKKw==" />
</div>
<div>
<span id="label1">Label</span>
</div>
</form>
</body>
</html>The view state is stored in the hidden field named __VIEWSTATE. View state is a Base64-encoded string. In this example the amount of text stored in the view ...