C# 4 and .NET 4

1244 ❘ ChaPTer 42 Asp.net dynAmic dAtA And mvc
Both dynamic data and MVC make use of another methodology that was introduced in .NET 3.5, routing.
This makes it possible for URLs to be simplifi ed and to include additional information, and is the fi rst thing
you will look at in this chapter. After routing, this chapter moves on to dynamic data and MVC in turn,
with a fi nal section about how to combine these technologies.
Both dynamic data and MVC are large subjects to cover and would require multiple
chapters to cover in depth. This chapter gives a general overview of using these
frameworks, which will hopefully give you enough information to get started before
fi n d i ng m o re i n - d e pt h re so u rc e s i f y o u wa n t t o u s e t he m i n m o re d e pt h.
rouTing
ASP.NET routing is a technology that enables you to assign sensible, human - readable URLs to web pages.
Essentially, this means that the URL for a web page that a user sees in the address bar of a browser doesn ’ t
necessarily match the physical location of a web page. Instead, the URL will include information that your
web site can use to map to a page that you defi ne, and can pass parameters to that page.
At fi rst glance, this may seem a little counterintuitive. Why wouldn ’ t you want users to see the address of
a web page Surely not exposing this information will make it more diffi cult to locate resources. In fact,
as you will see in this section, mapping URLs can make it much easier for users, and it has several other
benefi ts as well.
As an example, consider the following URL:
http://www.myecommercesite.com/products/kites/reddragon
Without knowing anything about the web site that uses this URL, you can probably take a good guess at
what you ’ d fi nd on the page. From the words in the URL, you would expect to see a product page for a kite
called “ Red Dragon. ”
The advantages of this type of URL are as follows:
➤
➤
➤
➤
Users can see at a glance what pages are.
URLs are easy for users to remember, even without creating bookmarks.
Users can modify URLs manually to navigate (for example, a user might replace the last section of the
above URL with /products/balloons).
Search engine results are optimized for these descriptive URLs, so the page ranking will be higher.
There are essentially two ways to implement URLs of this form. You can either create a page for every possible
URL, or you can use a framework that maps URLs to pages that can display data for multiple URLs.
This fi rst possibility is worth mentioning, as it isn ’ t necessarily out of the question — it is possible
to create static HTML sites that are generated from back - end data. However, this requires a fair amount of
maintenance and, in most situations, can be more trouble than it ’ s worth. Now that the tools have matured
the second scenario is more practical.
In fact, ASP.NET has included the capability to use URLs like this for some time, although “ URL rewriting
” (as it was known in earlier versions of ASP.NET) required an in - depth knowledge of the ASP
.NET architecture and could be quite tricky to implement. With the advent of ASP.NET routing, things
have become much easier.
In this section, you will look at the following:
➤
Query string parameters — Before looking at routing specifi cally, it is worth understanding the case
for including additional data in URLs in more detail. Query string parameters provide an alternative
way of doing this, and have existed since the very beginnings of the web. However, while simpler than
routing, they do not include all of the advantages.
www.it-ebooks.info