Home > Articles > Programming > ASP .NET

Creating ASP.NET Applications

Learn how to work with ASP.NET applications, including creating global variables and objects by storing information in application state, using the Global.asax file, configuring an application with the Web.Config and Machine.Config configuration files, and creating custom HTTP handlers and modules.
This sample chapter is excerpted from ASP.NET Unleashed (Sams, 2001, ISBN: 0672320681), by Stephen Walther.
This chapter is from the book

This chapter is from the book

In this chapter

  • Overview of ASP.NET Applications 
  • Using Application State 
  • Using the Web.Config File 
  • Using HTTP Handlers and Modules

In this chapter, you learn how to work with ASP.NET applications. First, you learn how to create global variables and objects by storing information in application state. Next, you learn how to use the Global.asax file, a special file that represents the current application so that you can use it to handle application wide events.

You also examine how to configure an application with the Web.Config and Machine.Config configuration files. You examine the standard sections of the Web.Config file so that you understand how to add new sections of your own.

Finally, you learn how to create custom HTTP handlers and modules. You can use a custom HTTP handler to perform custom logic when a request is made to a certain page. A custom HTTP module can be used to perform custom logic on each page request. At the end of this chapter, you learn how to create a WhosOn application with a custom HTTP handler and module that display statistics on the current users at your Web site.

Overview of ASP.NET Applications

An ASP.NET application consists of all files located within a particular virtual directory. The virtual directory can be the default directory (the wwwroot directory), or it can be a new virtual directory that you have defined by using the Internet Services Manager.

To create a new virtual directory, follow these steps:

  1. Launch Internet Services Manager by going to Start, Administrative Tools, Internet Services Manager.

  2. Right-click your default Web site and choose New, Virtual Directory.

  3. Provide the virtual directory with an alias (for example, myApp).

  4. Choose a physical directory for the virtual directory. It can be located anywhere on your hard drive.

  5. Choose the access permissions for the virtual directory. You need to enable both Read and Run scripts to execute ASP.NET pages.

After you create a new application by creating a virtual directory, you can access pages in the application by using URLs that look like this:

http://yourSite.com/myApp/default.aspx

This URL accesses a page located in the myApp application.

All the pages running in an application are isolated within an application domain. Separating a Web site into multiple application domains, by creating virtual directories, has a number of benefits:

  • Code that executes within one application cannot directly access code or resources in another application. So, you can host multiple applications on a single Web server without worrying about unintended interactions between the different applications.

  • If one application is shut down (or it crashes), it has no effect on other applications running on the same server. Therefore, flaky code executing in a preproduction Web site can be isolated from code running on a live Web site.

  • Assemblies in one domain are not shared with other domains. For example, one application can use a different version of a component without any conflict with other applications.

  • You can set application wide security policies. The code executing in a trusted application domain can be subject to a different set of permissions than code running in another untrusted application domain.

  • You can specify configuration settings that apply to one application and not another. For example, you can enable tracing and debugging for one application and not another application.

Every application can contain a special directory and two special files. The special directory is named /bin. This directory must be located in the root directory of the application.

NOTE

After you create a new virtual directory, you need to add the /bin directory to the application yourself.

The /bin directory contains custom components and controls (in the form of assemblies). Any component or control added to the /bin directory is automatically visible to all pages executing within the application. For example, if you create a new custom control named SuperDataGrid, you need to place this control in the /bin directory so that you can use it in your ASP.NET pages.

ASP Classic Note

In versions of Active Server Pages prior to ASP.NET, you needed to shut down the current application before you modified any of the components in an application. When using ASP.NET, in contrast, you can simply replace an old component with the new component in the /bin directory.

An application can also contain a special file named Global.asax. This file also must be located in the root directory of an application.

The Global.asax file contains subroutines that handle application wide events and objects declared with application scope. You learn how to create this file later in this chapter in the section titled "Using the Global.asax File."

Finally, an application can contain in its root directory a Web.Config file that specifies configuration information for the entire application. You learn how to use this file later in this chapter in the section titled "Using the Web.Config File."

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