C# 4 and .NET 4

1152 ❘ ChaPTer 40 cOre Asp.net
It may seem strange that the facility to add JavaScript code to your pages is included with ASP.NET.
However, JavaScript allows you to add dynamic client-side behavior to your web pages and can be very
useful. This is especially true for Ajax programming, as you will see in Chapter 41, “ASP.NET Features.”
It is possible to create ASP.NET files in Visual Studio, which is great for you, as you are already familiar
with this environment for C# programming. However, the default project setup for web applications in this
environment has a slightly more complex structure than a single .aspx file. This isn’t a problem for you,
however, and does make things a bit more logical (more programmer-like and less web developer–like).
For this reason, you will use Visual Studio throughout this chapter for your ASP.NET programming
(instead of Notepad).
The .aspx files can also include code in blocks enclosed by tags. However, function definitions
and variable declarations cannot go here. Instead, you can insert code that is executed as soon as the block
is reached, which is useful when outputting simple HTML content. This behavior is similar to that of
old-style ASP pages, with one important difference — the code is compiled, not interpreted. This results in
far better performance.
Now it’s time for an example. In Visual Studio, you create a new web site by using the File ➪ New ➪ Web
Site . . . menu option or a web application through the File ➪ New ➪ Project . . . menu option by selecting
a web application template. In either case, from the dialog box that appears, select the Visual C# language
type and the specific template you want. For web sites, you have an additional choice to make. Visual Studio
can create web sites in a number of different locations:
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On your local IIS web server
On your local disk, configured to use the built-in Visual Web Developer web server
At any location accessible via FTP
On a remote web server that supports Front Page Server Extensions
The latter two choices use remote servers so you are left with the first two choices. In general, IIS is the best
place to install ASP.NET web sites because it is likely to be closest to the configuration required when you
deploy a web site. The alternative, using the built-in web server, is fine for testing but has certain limitations:
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Only the local computer can see the web site.
Access to services such as SMTP is restricted.
The security model is different from IIS — the application runs in the context of the current user
rather than in an ASP.NET-specific account.
This last point requires clarification because security is very important when it comes to accessing databases
or anything else that requires authentication. By default, web applications running on IIS do so in an
account called ASPNET on IIS5 web servers, or in an account called NT AUTHORITY\NETWORK
SERVICE on IIS6 and above. This is configurable if you are using IIS, but not if you use the built-in
web server.
For the purposes of illustration, however, and because you may not have IIS installed on your computer,
you can use the built-in web server. You aren’t worried about security at this stage, so you can go with
simplicity.
Web applications don’t prompt you to choose a location like web sites do. Instead, web sites
must be deployed to web servers in a separate step — although for testing they will use the VWD
web server.
Create a new ASP.NET web site called PCSWebSite1 using the File System option and the Empty Web Site
template, at C:\ProCSharp\Chapter40, as shown in Figure 40-2.
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