Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

Storing an Object Reference in Session  (VB.NET)

Posted on 2011-03-14
6
564 Views
Last Modified: 2013-11-27
Hi -

I want to store an object reference in memory so I can access user info from page to page.   It's a 2-part question, the first being how do I store the object reference in session, and secondly, how do I access it?

The first part I cannot get to work and the following is a simplified version of my code:

Namespace User
     Public Class User

         Public CID As String = ""
         Public UserID As String = ""
         Public UserName As String = ""
         Public UserFirstName As String = ""
         Public UserSurname As String = ""
         
          Public Sub GetUser(ByVal UID As String)

               (code here would go to the DB and get the user based in the supplied UID)

               CID = "123456"
               UserID = "567890"
               UserName = "fbloggs"
               UserFirstName = "Fred"
               UserSurname = "Bloggs"
          End Sub

     End Class
End Namespace

Open in new window



On my aspx page, either of the following does not work:

Dim UserData As New User.User
Session("Test") = UserData.GetUser(UN)

Open in new window


or

Dim UserData As New User.User
dim UserTest as Object
UserTest = UserData.GetUser(UN)
Session("Test") = UserTest

Open in new window


Both ways throw an error of: "Expression does not produce a value".

I understand why it's throwing an error, but can't understand how to just reference the object with it's filled variables in the session, so I can then access it on other pages.

Thanks.
0
Comment
Question by:justinkent
  • 3
  • 3
6 Comments
 
LVL 52

Expert Comment

by:Carl Tawn
ID: 35128306
Well there is nothing wrong with the way you are trying to assign to the session, so there must be a problem with either the User class itself, or the GetUser() method.
0
 
LVL 52

Accepted Solution

by:
Carl Tawn earned 500 total points
ID: 35128320
Actually reading your code (properly this time). Your GetUser() method is a sub, not a function, so it doesn't return a value, hence you cannot directly assign it to the session.

You would have to do:
Dim UserData As New User.User
UserData.GetUser(UN)

Session("Test") = UserData

Open in new window

0
 

Author Comment

by:justinkent
ID: 35128648
Thanks very much Carl, that does now allow me to store the object in the session.

And how would I then access the variables in that object in subsequent pages?
0
Resolve Critical IT Incidents Fast

If your data, services or processes become compromised, your organization can suffer damage in just minutes and how fast you communicate during a major IT incident is everything. Learn how to immediately identify incidents & best practices to resolve them quickly and effectively.

 

Author Comment

by:justinkent
ID: 35128681
Actually, I think I figured it:

Something like this?

   Dim testData As User.User = Session("Test")
   Response.Write("CID = " & testData.CID)

Open in new window


It works...  Would this be correct and proper way?
0
 
LVL 52

Expert Comment

by:Carl Tawn
ID: 35128693
You can't read properties from the object directly from the session. You need to pull your object out first and cast it to the correct type, then you can work with it:
Dim user As UserData = CType(Session("Test"), UserData)

'// quick sanity check
If Not user Is Nothing Then

     '// we have a valid object so we can now read from it
     Response.Write(user.UserFirstName)

End If

Open in new window

0
 

Author Comment

by:justinkent
ID: 35128743
Fantastic, thank you.

:o)
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Real-time is more about the business, not the technology. In day-to-day life, to make real-time decisions like buying or investing, business needs the latest information(e.g. Gold Rate/Stock Rate). Unlike traditional days, you need not wait for a fe…
If you need to start windows update installation remotely or as a scheduled task you will find this very helpful.
Get people started with the process of using Access VBA to control Excel using automation, Microsoft Access can control other applications. An example is the ability to programmatically talk to Excel. Using automation, an Access application can laun…
Get people started with the utilization of class modules. Class modules can be a powerful tool in Microsoft Access. They allow you to create self-contained objects that encapsulate functionality. They can easily hide the complexity of a process from…

861 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question