ASP.NET MVC Controller recommendation for LINQ DataContext instantiation place

Question

How should I instantiate the datacontext (entity fw) in a MVC Controller:

• a) as a property in class
• b) as a field in class
• c) as a variable in Action
• d) as abstract away your DbContext with the Repository pattern

In WebForms I would use c), because b) would maintain the db object state across events, which is usually not what I want.

I actually never used a).

Answer 1

I'd like to start by saying that I 100% agree with @jrummell in that the DbContext should be instantiated. However, if you aren't going to do that, I would use a private readonly field and provide two constructors:

public MyController() : this(new DbContext()) { }

public MyController(DbContext context)
{
   this._dbContext = context;
}

This way you can still inject a DbContext for testing.