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Using the DbContextManager

The DbContextManager class allows the sharing of DbContext (with underlying ObjectContext) classes in Entity Framework. The good thing about this is that the same context can be used in the same scope without having to recreate the same type of the same context over and over again.

A very good example of this scoping is an ASP.NET (MVC) application where a context is normally shared throughout the whole thread that handles a request. A big advantage of reusing the same instance of a context is that already fetched entities don’t need to be refetched over and over again.

Obtaining a DbContext

Obtaining a DbContext is very simple by using the DbContextManager.

using (var dbContextManager = DbContextManager<MyEntities>.GetManager())
{
    var dbContext = dbContextManager.DbContext;
 
    // TODO: handle logic with dbContext here
}

It is very important to wrap the DbContextManager in a using state because it must be disposed

  Scoping is all done automatically because when a DbContextManager is instantiated, a reference counter is increased. Every time an instance of the DbContextManager is disposed, the reference counter is decreased. When the reference count reaches zero (0), it will dispose the DbContext that it manages.

Sharing a single DbContext per ASP.NET request

When a request is started, a context can be created by calling this code:

DbContextManagerHelper.CreateDbContextForHttpContext<MyEntities>();

When a request is ended, the context can be disposed by using this code:

DbContextManagerHelper.DisposeDbContextForHttpContext<MyEntities>();

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