Chapter 15: Managing Cache and State for ASP.NET

Preserving Content and Data Between Web Program Executions

You need not look far to find an example of state and cache management on the Web these days. For example, I have often used a very popular travel Web site to expedite my travel arrangements. For me, one of the site's most impressive features is demonstrated each time I navigate through the site, backward and forward, pricing and then repricing my product selections. All preferences and selections I enter on one page are conveniently stashed away, saved, and then displayed as appropriate.

It is easy to see why I referred earlier to the topic of state and cache management as a way to add value to your ASP.NET application (see the section "Making Your ASP.NET Applications Interactive" in Chapter 14). Each time I return to this travel Web site, I am quickly reminded of the pleasurable experience I had when I used the site before. I appreciate how the site "remembers" me by greeting me by name and making available to me my previous itineraries .

Note  

The travel site I refer to in the preceding paragraph is Expedia.com ( http://www.expedia.com ). Given that this is not an endorsement of any kind, I would like my mention of the site here to be viewed as just an acknowledgement , a case study of state management. I am only referring to this particular company as an example. I am sure that many other travel Web sites also offer these types of user interface features.

Does this remind you of your own experiences as a Web user? Think about it. Are you generally happy to have your personalized display preferences saved for you? How about those multipage questionnaires? Do you appreciate having previously entered data not disappear when you navigate around a site? As you may have guessed, you can programmatically address each of these concerns (and more) with ASP.NET's state and cache management features.

In this chapter, you will sort out the many options available when you want to enhance your ASP.NET applications with state and cache management. I begin this chapter's discussion with a brief review of the legacy mainframe CICS environment and the methods generally used to "manage state." This will help establish a perspective toward the need to preserve data. Next, I discuss the ASP.NET approach to cache management. I end the chapter with a discussion of ASP.NET state management features, both client based and server based.