Entity Framework Object Context in ASP.NET Session object?

Question

We have a multi-layered Asp.NET Web Forms application. The data layer has a class called DataAccess which impements IDisposable and has an instance

Answer 1

You should use one ObjectContext per request, you shouldn't store it is Session. It is easy to ruin data in ObjectContext stored for a long time:

1. What if you insert data that don't violate rules in ObjectContext, but violate rules in database? If you insert a row that violates the rules, will you be deleting it from context? Image situation: You use one context and suddenly you have request that changes data in one table, adds row to another table, then you call SaveChanges(). One of changes throws constraint violation error. How do you clean it up? Cleaning context is not easy, it is easier just to get new one in next request.

2. What if someone deletes data from database, while it is still in context? ObjectContext caches data and doesn't look from time to time to check if it is still there or if they changed:)

3. What if someone changes web.config and Session is lost? It seems as if you want to rely on Session to store information about logged in user. Forms authentication cookie is more reliable place to store this information. Session can be lost in many situations.

ObjectContext was designed to be short lived, it is best to create it in request when needed and dispose at the end of it.

If context per request doesn't work for you, you are propably doing something wrong, but don't make it worse by using Session.