Using the Object Model as a Road Map
While being able to create a page dynamically is a nice
feature, the real power of Active Server Pages comes from its ability to create
web-based applications. These applications allow the user to perform tasks that
go beyond simply requesting pages. The logic and structure to create these
applications are laid out in the object model.
We can use the object model as a road map that lays out:
Where information should be stored in our applications
How information specific to a single user can be
How to set up client pages to send the appropriate
information to the server for it to dynamically build a page
How to dynamically build a page, using all of the
features that ASP provides, and then send that page back to the client
In the next few chapters, we will be walking through this
landscape in detail and build up the expertise needed to put together an
application using Active Server Pages.
In this chapter, we have introduced the concept of objects.
For our purposes, an object is a programmatic tool that enables us to access a
physical item, or a set of associated data. An object is described by its
interfaces. These interfaces are broken into three categories:
Properties – a property's value holds data that
describes an attribute of the object.
Methods are used to have the object perform some task
Events let the object notify us that something has
happened and can also be raised to make something happen and can contain code
that we write that can be executed.
In learning how to develop with objects, we have seen how
Set and retrieve information from the object's
Call the methods of an object
With the concepts of objects well in hand, we introduced the
Active Server Pages object model. These seven objects encapsulate the
functionality offered by the ASP server.
The Server object provides basic functionality
across the web server.
The Application and Session objects provide
the application functionality that is not present in a basic web server.
The Request and Response objects are used
to interpret the information sent by the client and then construct the HTML
page that will be sent back in response.
The ObjectContext object, which is used to
control transactions within a web page.
The Error object that handles any ASP-generated
By understanding the relationships of these objects to one
another, we can start to build true applications by using the power of Active
Server Pages. The next few chapters will begin to show us how.