Beginning Web Development, Silverlight, and ASP.NET AJAX

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CHAPTER 2 ■ BASICS OF WEB DEVELOPMENT WITH ASP.NET
As you can see, the stock quote application as rendered by the browser is very different
from the stock quote application you saw in Listing 2-1. The controls have
been replaced by pure HTML, the text box has been replaced by an input control of
type "text", the button has been replaced by a form input control of type "submit", and
the label has been replaced by an HTML span. There are also a couple of new, hidden
input controls, called __VIEWSTATE and __EVENTVALIDATION, which contain a series of
characters.
These fields simply contain a binary serialized representation of the page controls
that are passed to the server and deserialized when the page inputs are submitted, or
posted back, to the server. The server then uses this information to retrieve the contents
of the controls (e.g., to reconstitute the text in the text box if the page is rerendered) and
to change them when necessary (e.g., to set the value of the label). This is the concept of
page state management, which is implemented for you by ASP.NET.
Using the Web Configuration File
When you first ran the stock quote application, the IDE should have noticed that debugging
wasn’t enabled, and would have asked if you wanted a default Web.config with
debugging enabled. If you chose Yes, your project directory will include a new file,
Web.config.
This file is used to define how the .NET Framework should handle your site. Information
such as security, caching, debugging, and globalization settings are typically stored
in Web.config.
Here’s an example of the Web.config file: