C# 4 and .NET 4

asP.neT Web forms ❘ 1159
This time, the value of the view state contains more information because the HTML result relies on more
than the default output from the ASP.NET page. In complex forms this can be a very long string indeed,
but you shouldn ’ t complain because so much is done for you behind the scenes. You can almost forget about
state management, keeping fi eld values between posts, and so on. Where the length of the view state string
becomes a problem, you can disable the view state for controls that do not need to retain state information.
You can also do this for entire pages if you want, which can be useful if the page does not ever need to
retain state between postbacks to improve performance.
For more on view state, see Chapter 41.
To convince yourself that you don ’ t need to perform any compilation for web sites manually, try changing
the text “ Button clicked! ” in Default.aspx.cs to something else, saving the fi le, and clicking the button
again. The text on the web page should change appropriately.
The Control Palette
This section takes a quick look at some of the available controls before you put more of them together into
a full, and more interesting, application. Figure 40 - 6 shows the toolbox that you see
when editing ASP.NET pages.
Note that the following control descriptions discuss properties; in all cases, the
corresponding attribute for use in ASP.NET code is identically named. This section
isn ’ t an attempt to provide a complete reference, so instead, we focus on only the
most frequently used controls and properties. The controls you see in this chapter
are in the Standard, Data, and Validation categories. The Navigation, Login, Web
Parts, and AJAX Extensions categories are covered in Chapter 41. The Reporting
controls to be presented on web pages, which enable reporting information,
including Crystal Reports, are not covered in this book.
Standard Web Server Controls
figure 40-6
Almost all the web server controls (in this and other categories) inherit from
System.Web.UI.WebControls.WebControl , which in turn inherits from System.Web.UI.Control .
Those that don ’ t use this inheritance instead derive either directly from Control or from a more specialized
base class that derives (eventually) from Control . As a result, the web server controls have many common
properties and events that you can use as required. There are quite a few of these, so we won ’ t attempt to
cover them all, just as with the properties and events of the web server controls themselves.
Many of the frequently used inherited properties are those that deal with display style. This can be
controlled simply, using properties such as ForeColor , BackColor , Font , and so on, but can also
be controlled using CSS classes. To use CSS styling, you set the string property CssClass to the name of
a CSS class in a separate fi le. You can use the CSS Properties window along with the style management
windows to assist you with CSS control styling. Other notable properties include Width and Height to
size a control, AccessKey and TabIndex to ease user interaction, and Enabled to set whether the control ’ s
functionality is activated in the Web Form.
Some controls can contain other controls, building up a control hierarchy on a page. You can get access to
the controls contained by a given control using its Controls property, or to the container of a control via
the Parent property.
You are likely to use the inherited Load event most often, to perform initialization on a control, and
PreRender to perform last - minute modifi cations before HTML is output by the control.
Plenty more events and properties exist, and you see many of these in more detail in the next chapter. In
particular, Chapter 41 deals with more advanced styling and skinning techniques. The following table
describes the standard web server controls in more detail.
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