Entity Framework and calling context.dispose()

Solution 1:

In fact this is two questions in one:

1. When should I Dispose() of a context?
2. What should be the lifespan of my context?

Answers:

1. Never ¹. using is an implicit Dispose() in a try-finally block. A separate Dispose statement can be missed when an exception occurs earlier. Also, in most common cases, not calling Dispose at all (either implicitly or explicitly) isn't harmful.

2. See e.g. Entity Framework 4 - lifespan/scope of context in a winform application. In short: lifespan should be "short", static context is bad.

¹ As some people commented, an exception to this rule is when a context is part of a component that implements IDisposable itself and shares its life cycle. In that case you'd call context.Dispose() in the Dispose method of the component.

Solution 2:

I followed some good tutorials to use EF and they don't dispose the context.

I was a bit curious about that and I noticed that even the well respected Microsoft VIP don't dispose the context. I found that you don't have to dispose the dbContext in normal situation.

If you want more information, you can read this blog post that summarizes why.

Solution 3:

Better still:

public static string GetName(string userId)
{
    using (var context = new DomainDbContext()) {
        return context.UserNameItems.FirstOrDefault(x => x.UserId == userId);
    }
}

No need to return the result from outside the using scope; just return it immediately and you'll still get the desired disposal behavior.