CHAPTER 1 ?– SERVER CONTROL BASICS 11
Figure 1-5. Adding an event handler to the TextChanged event of the TextBox control
Figure 1-6. The completed ???Hello, World??? demonstration web form
The Web Page As a Control Tree
ASP.NET provides full programmatic access to the tags on an HTML page in an object-oriented
way. The architecture in ASP.NET that provides this capability is the .aspx page control tree. In
this section, we discuss the control tree as it relates to the ???Hello, World??? example.
12 CHAPTER 1 ?– SERVER CONTROL BASICS
At first glance, the ???Hello, World??? web form would seem to contain only a few visible server
controls that were explicitly placed on the form. The reality is that the entire display surface of
the .aspx page becomes a cornucopia of controls during processing. Any HTML content in the
web form that is not part of the server controls laid out in the Visual Studio Designer is packaged
into a server control that renders the HTML. The control structure of the web form can be seen
by turning on the trace features of ASP.NET through setting the Trace=True attribute on the
Page directive:
<%@ Page Language="C#" Trace="true"
MasterPageFile="../Master Page/ControlsBook2MasterPage.master"
AutoEventWireup="true" CodeFile="HelloWorld.
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