How to access session variables from any class in ASP NET

Question

I have created a class file in the App Code folder in my application  I have a session variable   Session  loginId     I want to access this session variables in my class  but when I am writing the following line then it gives error  Session  loginId     Can anyone tell me how to access session variables within a class which is created in app code folder in ASP NET 2 0  C

User · Answer

The answers presented before mine provide apt solutions to the problem, however, I feel that it is important to understand why this error results:

The Session property of the Page returns an instance of type HttpSessionState relative to that particular request. Page.Session is actually equivalent to calling Page.Context.Session.

MSDN explains how this is possible:

Because ASP.NET pages contain a default reference to the System.Web namespace (which contains the HttpContext class), you can reference the members of HttpContext on an .aspx page without the fully qualified class reference to HttpContext.

However, When you try to access this property within a class in App_Code, the property will not be available to you unless your class derives from the Page Class.

My solution to this oft-encountered scenario is that I never pass page objects to classes. I would rather extract the required objects from the page Session and pass them to the Class in the form of a name-value collection / Array / List, depending on the case.

User · Answer

The problem with the solution suggested is that it can break some performance features built into the SessionState if you are using an out-of-process session storage   either  State Server Mode  or  SQL Server Mode    In oop modes the session data needs to be serialized at the end of the page request and deserialized at the beginning of the page request  which can be costly   To improve the performance the SessionState attempts to only deserialize what is needed by only deserialize variable when it is accessed the first time  and it only re-serializes and replaces variable which were changed   If you have alot of session variable and shove them all into one class essentially everything in your session will be deserialized on every page request that uses session and everything will need to be serialized again even if only 1 property changed becuase the class changed   Just something to consider if your using alot of session and an oop mode

User · Answer

Access the Session via the thread s HttpContext - HttpContext Current Session  quot loginId quot

User · Answer

In asp net core this works differerently   public class SomeOtherClass       private readonly IHttpContextAccessor  httpContextAccessor      private ISession  session   gt   httpContextAccessor HttpContext Session       public SomeOtherClass IHttpContextAccessor httpContextAccessor                 httpContextAccessor   httpContextAccessor             public void TestSet                  session SetString  Test    Ben Rules                public void TestGet                 var message    session GetString  Test              Source  https   benjii me 2016 07 using-sessions-and-httpcontext-in-aspnetcore-and-mvc-core

User · Answer

Updated for completeness  You can access session variables from any page or control using Session  loginId   and from any class  e g  from inside a class library   using System Web HttpContext Current Session  loginId     But please read on for my original answer       I always use a wrapper class around the ASP NET session to simplify access to session variables   public class MySession          private constructor     private MySession               Property1    default value                 Gets the current session      public static MySession Current             get                 MySession session              MySession HttpContext Current Session    MySession              if  session    null                      session   new MySession              HttpContext Current Session    MySession       session                    return session                             add your session properties here  e g like this      public string Property1   get  set        public DateTime MyDate   get  set        public int LoginId   get  set        This class stores one instance of itself in the ASP NET session and allows you to access your session properties in a type-safe way from any class  e g like this   int loginId   MySession Current LoginId   string property1   MySession Current Property1  MySession Current Property1   newValue   DateTime myDate   MySession Current MyDate  MySession Current MyDate   DateTime Now    This approach has several advantages    it saves you from a lot of type-casting you don t have to use hard-coded session keys throughout your application  e g  Session  loginId   you can document your session items by adding XML doc comments on the properties of MySession you can initialize your session variables with default values  e g  assuring they are not null

User · Answer

I had the same error  because I was trying to manipulate session variables inside a custom Session class   I had to pass the current context  system web httpcontext current  into the class  and then everything worked out fine   MA

User · Answer

This should be more efficient both for the application and also for the developer   Add the following class to your web project        lt summary gt      This holds all of the session variables for the site       lt  summary gt  public class SessionCentralized   protected internal static void Save lt T gt  string sessionName  T value        HttpContext Current Session sessionName    value     protected internal static T Get lt T gt  string sessionName        return  T HttpContext Current Session sessionName      public static int  WhatEverSessionVariableYouWantToHold       get               return Get lt int  gt  nameof WhatEverSessionVariableYouWantToHold              set               Save nameof WhatEverSessionVariableYouWantToHold   value                Here is the implementation   SessionCentralized WhatEverSessionVariableYouWantToHold   id

[c#] How to access session variables from any class in ASP.NET?

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