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If you model your Web application to follow a particular
navigation path, you probably wrapped up your navigation paths through an
action or a verb. This action or verb is usually realized as a function name.
That function provides the means necessary to navigate through the different
stages of a site.
However, sometimes you may want to encapsulate the
navigation through a single point of entry, such as for wizard-type
applications. As the user progresses through the particular stages of an
application, different actions occur for collecting data. Any single action
refers back to the same entry page where the business logic determines to what
stage the user should be directed.
Putting all this business logic in one source is feasible,
but it can get difficult to manage. In order to provide the single point of
entry while dividing up responsibility, use the Server.Execute
method in ASP.
Managing apps using the Server.Execute method
The Server.Execute method takes an ASP page as a parameter
and passes the functionality on to it. The defined page runs as a separate
process yet its output goes to the existing Response and can access all the QueryString and Form data of the Request object. This makes
it handy to manage resources since you don’t have to instantiate all the
resources that you might need if you were to put all your logic in one page.
Let’s say you were creating an application that gathered
user information for a particular use case. Let’s say the use case is “Input
Shipping Information”. In order to guide the user through a particular sequence
for this use case, you want to collect the shipping address, you want to
collect the carrier information, and you want to display the shipping detailed
information and have the user okay this information. You have one page, InputShippingInformation.asp. Through this one page you realize the
following actions: GetShippingAddress, GetCarrier, GetCarrierDetails, ReviewShipping, and SubmitShipping.
The result of each action is InputShippingInformation.asp.
The coordinating function for each action uses the Server.Execute method to
direct the process to the coordinating page. View the sample in Listing A.
From this code snippet, you can see that the navigation is
executed through an “actionverb” Request item. In
each function (or Sub) that realizes the action, the Server.Execute moves
execution to the specified ASP page. When the specified page receives
execution, only the Application, Session, and Request objects transfer any
application data. Any local objects or variables that you defined and used in
the InputShippingInformation.asp page are no longer
Unlike the Response.Redirect
method, the browser is not instructed to navigate to another page. Therefore,
the browser still thinks that it is navigated to InputShippingInformation.asp.
This can also add some level of security to your application. View the GetShippingAddress.asp page in
Notice that I did not specify an action attribute for the
FORM tag. The browser will submit the information to the current page when the
submit event occurs. This helps make this particular page usable not only in
the InputShippingInformation.asp page, but also anywhere you need to call a Server.Execute method to
gather shipping information. Also, I ended the Response with the End method, because after the Executed page is complete execution will return back to the calling page.
The Member object is an object that contains information
about the currently logged in user. (For simplicity’s sake, I’m not going to go
into the details on how to create this functionality.) Using the Member
information, I can pre-populate the data fields for the shipping address. Once
the user fills in the appropriate data fields and hits the Submit button, the “actionverb” form data sends the page to the next action.
If you would like to see the full source for this
application, you can download