Object Persistance Throughout Pages

[vbFace]

Suppose I create a custom class object, and I want this object to persist throught the pages of an on-line survey. How would I go about ensuring this persistence? Can I instantiate the object in the global.aspx Sub Session_Start(Sender As Object, E As EventArgs)? Or, can I assign this custom object as a property of the Session Object?

 

 

i.e

Sub Session_Start(Sender As Object, E As EventArgs)

Dim myCustObj as MyCustomClassObject

   Session("UserObject") = myCustObj

End Sub

[Bucky]

Yes, assign it to the Session variable like you're currently doing.

Then, to access it from a page, just cast it to the correct type.

 

For example:

 

Dim myCustObj As MyCustomClassObject

myCustObj = DirectCast(Session("UserObject"), MyCustomClassObject)
' Here you manipulate myCustObj

[Robby]

To add to Bucky's post...

 

In case myCustObj does not contain all expected values during Session_start you can assign to it from any page using the same method.

Session("UserObject") = myCustObj

[vbFace]

Very nice. Thanks guys.

 

Robby, do you mean that if I change the values in the object on a page, I have to re-assign the object to the Session object, so the new data in the object is available on the next page?

[Bucky]

Yes, that's correct.

[Jackpanel]

I'm looking for a similar solution, but have hit a snag.

 

I've created a custom Product class and compiled it. I can access it on the individual page using the following code:

 

<%
 Dim objProduct As Product
 objProduct = New Product()

 objProduct.ID = 123456
 objProduct.PartNumber = "Part Number 12345"
 objProduct.Description = "This is the description of the product"
 objProduct.Category = 1
 objProduct.QuantityPerUnit = 1
 objProduct.UnitSize = "each"
 objProduct.UnitSellPrice = 24.99

%>

 

However, when I try to declare a Product variable in my global.asax file as in your example:

 

   Sub Session_Start(Sender As Object, E As EventArgs)
       Dim objProduct As Product
       Session("objProduct") = objProduct
   End Sub

 

I get a error message saying "Compiler Error Message: BC30002: Type 'Product' is not defined." I know its not a problem with my Product class, since I can declare and manipulate it on other pages, but when I try to declare it in the session variable, it fails.

 

Any ideas?

[Bucky]

The problem does not lie in the setting of the variable to a

Session variable; it lies in the declaration of objProduct. Make

sure that the page has the correct Imports statement to

import the namespace that Product is declared in.