How do I use multiple databases with Autofac?

Question

I am having a project and my project is connecting to two different databases are BookStoreEntities and BlogEntities.

If I remove line code builder.RegisterType<BlogEntities>().As<DbContext>(); in Autofac configuration my project works fine and else I'll get error "The entity type Book is not part of the model for the current context".

My autofac config:

var builder = new ContainerBuilder();
builder.RegisterControllers(Assembly.GetExecutingAssembly());

builder.RegisterType<BookStoreEntities>().As<DbContext>();
builder.RegisterType<BlogEntities>().As<DbContext>();
builder.RegisterGeneric(typeof(Repository<>)).As(typeof(IRepository<>)).InstancePerDependency();
builder.RegisterType<BookService>().As<IBookService>();

builder.RegisterFilterProvider();
IContainer container = builder.Build();
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));

Repository class:

public class Repository<T> : IRepository<T> where T : class
{
    private DbContext _dbContext;
    private DbSet<T> _dbSet;

    public Repository(DbContext dbContext)
    {
        _dbContext = dbContext;
        _dbSet = dbContext.Set<T>();
    }

    public IEnumerable<T> GetAll()
    {
        return _dbSet;
    }
}

Service layer:

public class BookService : IBookService
{
    private IRepository<Book> _bookRepository;

    public BookService(IRepository<Book> bookRepository)
    {
        _bookRepository = bookRepository;
    }

    public IEnumerable<Book> GetBooks()
    {
        return _bookRepository.GetAll();
    }
}

Controller:

public class BookController : Controller
{
    private IBookService _bookService; 

    public BookController(IBookService bookService)
    {
        _bookService = bookService;
    }

    // GET: Book
    public ActionResult Index()
    {
        var books = _bookService.GetBooks();

        return View(books);
    }
}

CodeCaster · Accepted Answer · 2015-10-28 10:23:11Z

2

My Project is using 2 different databases and Service layer will implement from this Generic Repository. I want to myservice1 works with MyDbContext1 and myservice2 works with MyDbContext2

Then don't new your DbContext inside your repository. That makes testing hard anyway.

Inject it:

public Repository(DbContext dbContext)
{
    _dbContext = dbContext;
}

Now the repository doesn't care which DbContext-derived class is injected. This works because you only call DbContext.Set<T>().

answered Oct 28, 2015 at 10:23

CodeCaster

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4 Comments

Khiem Nguyen Over a year ago

I have tried this way and after I used Dependency Injection. can I register MyDbContext1 and MyDbContext2 as DbContext

CodeCaster Over a year ago

Maybe pretty obvious, but in service1 configure your IOC container to inject MyDbContext1, and in service2 configure your IOC container to inject MyDbContext2.

CodeCaster Over a year ago

No, you show your current code in your question first. :) I don't know what your "services" are nor how you currently set up your container.

Khiem Nguyen Over a year ago

I have resolved issue with this example github.com/raghav-rosberg/UnitOfWorkWithMultipleDBContext

Roman Marusyk · Accepted Answer · 2015-10-28 10:11:32Z

0

Try to something like:

public class MyDbContext1  : DbContext   
{
  public MyDbContext1 ()
    :base("ConnectionString")
  { }

  public new IDbSet<TEntity> Set<TEntity>() where TEntity : class
  {
    return base.Set<TEntity>();
  }

  protected override void OnModelCreating(DbModelBuilder modelBuilder)
  {
   //...
  }
}

And add to repository new property

private IDbSet<T> Entities
{
  get
  {
    if (_dbSet == null)
    {
      _dbSet = _dbContext1.Set<T>();
    }
    return _dbSet;
  }
}

answered Oct 28, 2015 at 10:11

Roman Marusyk

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3 Comments

Khiem Nguyen Over a year ago

yes I know, but current I want to add more a Context which called is MyDbContext2 and I'll implement in generic repository.

Roman Marusyk Over a year ago

It is a strange idea but what is the problem to add another dbcontexts ?

Khiem Nguyen Over a year ago

I have updated my question and I hope so obvious for you

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