DbContext，要注入还是不注入？

Question

This may well be a question with a million answers but it is bugging me a lot.

I have an mvc application using EF. Now do I inject the DbContext into my business objects or do I do it some other way?

I can obviously inject it but that way I end up using DbContext in my classes rather than a Typed Context. This means I have no intellisense and the code looks less graceful

eg

var test=(from d in context.Set<User>() where d.Username=="testname" select d).FirstOrDefault();

compared to the typed loveliness

var test=(from d in context.Users where d.Username=="testname" select d).FirstOrDefault();

Now I know this is not a massive issue but when writing tens of thousands of lines it is nice to have intellisense around, especially if other coders not so familiar with the code are helping out.

I know there is the unit of work pattern but this is in my opinion the work of the devil himself when EF is involved as it is effectively wrapping a repository pattern in a repository pattern which is just ludicrous. So this is not an option for me.

So do we inject and if so can we somehow end up with a typed context?

Or do we not inject?

Answer 1

Firstly, I think there might be some misunderstanding in the term 'inject'.

Inject means this:

public class UserService
{
    MyContext _db;

    public UserService(MyContext db)
    {
        _db = db;
    }

    public void GetUserById(string id)
    {
        _db.Users.First(x => x.Id = id);
    } 
}

Instead of this:

public class UserService
{
    MyContext _db = new MyContext();

    public UserService()
    {
    }

    public void GetUserById(string id)
    {
        _db.Users.First(x => x.Id = id);
    } 
}

Notice how in the first example MyContext is 'injected' into the constructor. In the second example, UserService itself creates a new instance of MyContext .

Now, should you? I believe you should, and in fact, it is an accepted good practice. Before you do, make sure to read and try it on a few sample projects to find out the benefits it brings you. Wikipidia: Dependency Injection Advantages