Question

The MiniProfiler site gives the following code for generating an Entity Framework ObjectContext:

public static MyModel Get()
{
  var conn =  new StackExchange.Profiling.Data.EFProfiledDbConnection(GetConnection(), MiniProfiler.Current);
  return ObjectContextUtils.CreateObjectContext<MyModel>(conn); // resides in the MiniProfiler.EF nuget pack
}

However, using Entity Framework 5, I am not using an ObjectContext – rather I am using a DbContext. I cannot plug the model name in here, since the CreateObjectContext<T>() method expects T to be of type ObjectContext. (For the same reason, the code given in this answer also doesn’t work).

Additionally, I am using autofac to initialize my Db connections. This is being registered with the following (MyData = the name of my EF DataContext):

Builder.RegisterType<MyData>().As<DbContext>().InstancePerHttpRequest();

So combining two parts: how can I use autofac to initialize my DbContext tied into MiniProfiler.EF? And if that is not possible, at least how can I do the first part (create a factory method for MiniProfiler.EF to return a DbContext)?

Answer 1

There is a constructor of the DbContext class which takes an existing DbConnection

So you need a new contructor on your MyData which just calls the base

public class MyData : DbContext
{
    public MyData(DbConnection existingConnection, bool contextOwnsConnection)
        : base(existingConnection, contextOwnsConnection)
    {
    }

    //..
}

Then you register your MyData with Register:

builder.Register(c => 
{
   var conn =  new EFProfiledDbConnection(GetConnection(), MiniProfiler.Current);
   return new MyData(conn, true);
}).As<DbContext>().InstancePerHttpRequest();