search
HomeBackend DevelopmentC#.Net TutorialDetailed introduction to session in ASP

Session object is used to store user information. Variables stored in the session object hold information about a single user and are available to all pages in an application.

Session Object

When you work with an application, you open it, make changes, and then close it. It's a lot like a conversation. The computer knows who you are. It knows when you open and close apps. But there's a problem on the Internet: Since HTTP addresses cannot persist state, the web server doesn't know who you are or what you do.

ASP solves this problem by creating a unique cookie for each user. The cookie is transferred to the client and contains information that identifies the user. This interface is called a Session object.

Session objects are used to store information about the user, or to change settings for a user's session. Variables stored in the session object hold information about a single user and are available to all pages in the application. The information stored in the session object is usually name, id, and parameters. The server creates a new Session for each new user and revokes the Session object when the session expires.

When does the Session start?

Session starts at:

*When a new user requests an ASP file, and the Global.asa file references the Session_OnStart subroutine;

*When a value is stored in a Session variable;

*When a user requests an ASP file, and Global.asa uses the tag to instantiate it through the session scope When a certain object;

When does the Session end?

If the user does not request or refresh the page in the application within the specified time, the session will end. The default value is 20 minutes.

If you want to set the timeout interval longer or shorter, you can set the Timeout

property.

The following example sets a timeout interval of 5 minutes:

<%
Session.Timeout=5
%>

To end the session immediately, use the Abandon method:

<%
Session.Abandon
%>

Note: The main issue when using sessions is when they should end. We won't know if the user's most recent request was the last request. So we don't know how long we should let the session "live". Waiting too long for an idle session can exhaust server resources. However, if the session is deleted prematurely, the user will have to start over again over and over again because the server has deleted all the information. Finding the right timeout interval can be difficult.

Tip: If you are using session variables, do not store large amounts of data in them.

Storing and retrieving session variables

The biggest advantage of the Session object is that variables can be stored in it for subsequent web page reading, and its application range is very wide of.

The following example assigns "Donald Duck" to the session variable named username, and assigns "50" to the session variable named age:

<%
Session("username")="Donald Duck"
Session("age")=50
%>

Once the value is stored in the session variable, it can be used by any page in the ASP application:

Welcome


The above The result returned by the program is: "Welcome Donald Duck".

You can also save user parameters in the session object, and then decide what page to return to the user by accessing these parameters.

The following example specifies that if the user uses a low monitor resolution, a text-only version of the page is returned:

<%If Session("screenres")="low" Then%> 
  This is the text version of the page
<%Else%> 
  This is the multimedia version of the page
<%End If%>

移除 session 变量

contents 集合包含所有的 session 变量。

可通过 remove 方法来移除 session 变量。

在下面的例子中,假如 session 变量 "age" 的值小于 18,则移除 session 变量 "sale":

<%
If Session.Contents("age")<18 then   Session.Contents.Remove("sale")End If 
%>

如需移除 session 中的所有变量,请使用 RemoveAll 方法:

<%
Session.Contents.RemoveAll()
%>

遍历 contents 集合

contents 集合包含所有的 session 变量。可通过遍历 contents 集合,来查看其中存储的变量:

<%
Session("username")="Donald Duck"
Session("age")=50
dim i
For Each i in Session.Contents
  Response.Write(i & "<br />")
Next
%>

结果:

username
age

如果需要了解 contents 集合中的项目数量,可使用 count 属性:

<%
dim i
dim j
j=Session.Contents.CountResponse.Write("Session variables: " & j)
For i=1 to j
  Response.Write(Session.Contents(i) & "<br />")
Next
%>

结果:

Session variables: 2
Donald Duck
50

遍历 StaticObjects 集合

可通过循环 StaticObjects 集合,来查看存储在 session 对象中所有对象的值:

<%
dim i
For Each i in Session.StaticObjects
  Response.Write(i & "<br />")
Next
%>

【相关推荐】

1.  ASP免费视频教程

2. 教你解决ASP session丢失的方法

3. 介绍ASP中Session对象的三种方法

4. 详解ASP中Session的使用技巧

5. ASP session简单示例

The above is the detailed content of Detailed introduction to session in ASP. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Developing with C# .NET: A Practical Guide and ExamplesDeveloping with C# .NET: A Practical Guide and ExamplesMay 12, 2025 am 12:16 AM

C# and .NET provide powerful features and an efficient development environment. 1) C# is a modern, object-oriented programming language that combines the power of C and the simplicity of Java. 2) The .NET framework is a platform for building and running applications, supporting multiple programming languages. 3) Classes and objects in C# are the core of object-oriented programming. Classes define data and behaviors, and objects are instances of classes. 4) The garbage collection mechanism of .NET automatically manages memory to simplify the work of developers. 5) C# and .NET provide powerful file operation functions, supporting synchronous and asynchronous programming. 6) Common errors can be solved through debugger, logging and exception handling. 7) Performance optimization and best practices include using StringBuild

C# .NET: Understanding the Microsoft .NET FrameworkC# .NET: Understanding the Microsoft .NET FrameworkMay 11, 2025 am 12:17 AM

.NETFramework is a cross-language, cross-platform development platform that provides a consistent programming model and a powerful runtime environment. 1) It consists of CLR and FCL, which manages memory and threads, and FCL provides pre-built functions. 2) Examples of usage include reading files and LINQ queries. 3) Common errors involve unhandled exceptions and memory leaks, and need to be resolved using debugging tools. 4) Performance optimization can be achieved through asynchronous programming and caching, and maintaining code readability and maintainability is the key.

The Longevity of C# .NET: Reasons for its Enduring PopularityThe Longevity of C# .NET: Reasons for its Enduring PopularityMay 10, 2025 am 12:12 AM

Reasons for C#.NET to remain lasting attractive include its excellent performance, rich ecosystem, strong community support and cross-platform development capabilities. 1) Excellent performance and is suitable for enterprise-level application and game development; 2) The .NET framework provides a wide range of class libraries and tools to support a variety of development fields; 3) It has an active developer community and rich learning resources; 4) .NETCore realizes cross-platform development and expands application scenarios.

Mastering C# .NET Design Patterns: From Singleton to Dependency InjectionMastering C# .NET Design Patterns: From Singleton to Dependency InjectionMay 09, 2025 am 12:15 AM

Design patterns in C#.NET include Singleton patterns and dependency injection. 1.Singleton mode ensures that there is only one instance of the class, which is suitable for scenarios where global access points are required, but attention should be paid to thread safety and abuse issues. 2. Dependency injection improves code flexibility and testability by injecting dependencies. It is often used for constructor injection, but it is necessary to avoid excessive use to increase complexity.

C# .NET in the Modern World: Applications and IndustriesC# .NET in the Modern World: Applications and IndustriesMay 08, 2025 am 12:08 AM

C#.NET is widely used in the modern world in the fields of game development, financial services, the Internet of Things and cloud computing. 1) In game development, use C# to program through the Unity engine. 2) In the field of financial services, C#.NET is used to develop high-performance trading systems and data analysis tools. 3) In terms of IoT and cloud computing, C#.NET provides support through Azure services to develop device control logic and data processing.

C# .NET Framework vs. .NET Core/5/6: What's the Difference?C# .NET Framework vs. .NET Core/5/6: What's the Difference?May 07, 2025 am 12:06 AM

.NETFrameworkisWindows-centric,while.NETCore/5/6supportscross-platformdevelopment.1).NETFramework,since2002,isidealforWindowsapplicationsbutlimitedincross-platformcapabilities.2).NETCore,from2016,anditsevolutions(.NET5/6)offerbetterperformance,cross-

The Community of C# .NET Developers: Resources and SupportThe Community of C# .NET Developers: Resources and SupportMay 06, 2025 am 12:11 AM

The C#.NET developer community provides rich resources and support, including: 1. Microsoft's official documents, 2. Community forums such as StackOverflow and Reddit, and 3. Open source projects on GitHub. These resources help developers improve their programming skills from basic learning to advanced applications.

The C# .NET Advantage: Features, Benefits, and Use CasesThe C# .NET Advantage: Features, Benefits, and Use CasesMay 05, 2025 am 12:01 AM

The advantages of C#.NET include: 1) Language features, such as asynchronous programming simplifies development; 2) Performance and reliability, improving efficiency through JIT compilation and garbage collection mechanisms; 3) Cross-platform support, .NETCore expands application scenarios; 4) A wide range of practical applications, with outstanding performance from the Web to desktop and game development.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

MinGW - Minimalist GNU for Windows

MinGW - Minimalist GNU for Windows

This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

SublimeText3 Linux new version

SublimeText3 Linux new version

SublimeText3 Linux latest version