Home > Articles > Programming > ASP .NET

State Management in ASP.NET

State management influences almost every aspect of a Web application's design. Take the steps to learn and understand all the options available for state management, as well as their implications for usability, performance, and scalability.
This chapter is from the book

Before we begin discussing state management in ASP.NET, let's get one thing straight: Attempting to manage state in Web applications goes against the fundamental design principles of the Web. One of the primary goals of the Web and its underlying protocol, HTTP, is to provide a scalable medium for sharing information. Adding user state inherently reduces scalability because the pages shown to a particular user will be different from those shown to another user and thus cannot be reused or cached.

In spite of this fact, many applications deployed on the Web require user-specific state to function properly. Applications ranging from e-commerce shopping sites to local company intranet sites depend on the ability to track individual requests from distinct users and store state on behalf of each client, whether it's items in a shopping cart or which days were selected on a calendar as requested vacation days. Although maintaining client-specific state is not officially part of the HTTP protocol, there is a proposal in place for adding state management to HTTP. RFC 210914 defines a proposed standard for state management for HTTP also known as cookies. Although it is only a proposed standard and not yet an official part of the HTTP specification, cookies are in widespread use today in almost all browsers, and many Web sites rely on cookies for their functionality.

As a consequence, Web programmers must be very conscious about state management. Unlike traditional applications, Web applications must be very explicit about any state that is maintained on behalf of a client, and there is no one standard way to maintain that state.

10.1 Types of State

One of the most important decisions you face when designing a Web application is where to store your state. ASP.NET provides four types of state: application state, session state, cookie state, and view state. In this chapter, we explore each type of state, when it is most applicable, and any disadvantages you should be aware of if you decide to make use of it.

ASP.NET, like its predecessor, ASP, provides a pair of objects for managing application-level state and session-level state. Application state is where information that is global to the application may be stored. For efficiency, this state is typically stored once and then read from many times. Session state is maintained on a per-client basis. When a client first accesses any page in an application, an ASP.NET generated session ID is created. That session ID is then transmitted between the server and the client via HTTP either using client-side cookies or encoded in a mangled version of the URL (URL mangling is discussed in detail later in this chapter). On subsequent accesses by the same client, state associated with that session ID may be viewed and modified. Cookies provide the ability to store small amounts of data on a client's machine. Once a cookie is set, all subsequent pages accessed by the same client will transmit the cookie and its value.

Finally, view state is a yet another way of storing state on behalf of a client by saving and restoring values from a hidden field when a form is posted. Although this technique for retaining state has been used by Web developers in the past, ASP.NET provides a simplified mechanism for taking advantage of it. As we have seen in Chapter 8, it is possible to place items into the ViewState property bag available in every Page-derived class. When that page issues a POST request to itself, the values placed in the ViewState property bag can then be retrieved, the key restriction being that view state works only when a page posts to itself. Table 10-1 summarizes the advantages and disadvantages of each of the four types of state available in ASP.NET.

Table 10-1: State Type Comparison in ASP.NET

Type of State

Scope of State

Advantages

Disadvantages

Application

Global to the application

  • shared across all clients
  • Overuse limits scalability
  • Not shared across multiple machines in a Web farm or processors in a Web garden
  • Primary purpose subsumed by data cache in ASP.NET

Session

Per client

  • Can configure to be shared across machines in a Web farm and processors in a Web Garden
  • Requires cookies or URL managing to mange client association
  • Off-host storage can be inefficient

Cookie

Per client

  • Works regardless of server configuration
  • State stored on client
  • State can live beyoond current session
  • Limited memory (-4KB)
  • Clients may not support cookies or may explicitly disable them
  • Stae is sent back and forth with each request

View

Across POST request to the same page

  • Works regardless of server configuration
  • State is retained only with POST request made to the same page
  • State is sent back and forth with each request

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020