DbContextScope with Generic Repository

Question

I am using the DbContextScope described here

In his example of how to get a hold of a dbcontext outside of the class its instantiated, Mehdi writes:

public class UserRepository : IUserRepository {
    private readonly IAmbientDbContextLocator _contextLocator;

    public UserRepository(IAmbientDbContextLocator contextLocator)
    {
        if (contextLocator == null) throw new ArgumentNullException("contextLocator");
        _contextLocator = contextLocator;
    }

    public User Get(Guid id)
    {
        return _contextLocator.Get<MyDbContext>.Set<User>().Find(id);
    } 
}

But, if im going for a generic repository, say

public abstract class RepositoryBase<T> : IRepository<T> where T : class, IDomainEntity
{
    private readonly DbSet<T> set;

    private IAmbientDbContextLocator contextLocator;

    protected RepositoryBase(IAmbientDbContextLocator ctxLocator)
    {
        if (ctxLocator == null) throw new ArgumentNullException(nameof(ctxLocator));
        contextLocator = ctxLocator;
    }

    public T Get(Guid id)
    {
        //return _contextLocator.Get<MyDbContext>.Set<T>().Find(userId);
    }
}

then how is the dbset supposed to be resolved? how do i work with "MyDbContext" in the Get method? i do have multiple contexts.

Erkan Demirel Erkan Demirel · Accepted Answer · 2016-03-08T13:29:47

   public abstract class RepositoryBase<T, TDbContext> : IRepository<T> where T : IDomainEntity where TDbContext : DbContext
    {
        private readonly DbSet<T> _dbset;
        private readonly IAmbientDbContextLocator _contextLocator;

        protected RepositoryBase(IAmbientDbContextLocator ctxLocator)
        {
            if (ctxLocator == null) throw new ArgumentNullException(nameof(ctxLocator));
            _contextLocator = ctxLocator;
            _dbset = _contextLocator.Get<TDbContext>.Set<T>();
        }

        protected DbSet<T> DbSet { get { return _dbset; } }
        public T Get(Guid id)
        {
            return DbSet.Find(id);
        }
    }

If you don't want TDbContext, You can send DbContext on constructor beside of contextlocator. But he forces you to use DbContextScope, I didn't read all article but let's not break his logic.

DbContextScope with Generic Repository

1 Answers