依赖注入的ASP.NET Core多重实现

Question

Is there a way I can designate multiple implementations of a single interface using ASP.NET Core? I could do this in Ninject like this:

ninjectKernel.Bind<DbContext>().To<OracleDbContext>().Named("UnitWork");
ninjectKernel.Bind<DbContext>().To<AppsDbContext>().Named("AppsWork");

Answer 1

If your question is specific to just DbContext then it's easy using the following statements

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<OracleDbContext>(builder => builder.UseSqlServer(connectionString));
    services.AddDbContext<AppsDbContext>(builder => builder.UseSqlServer(connectionString));
}

If your question relates to general interfaces, then it's possible only if it's a generic interface. Say you have an interface like below:

public interface IRepository<T>
{
}

And multiple implementations like:

public class GenericRepository<User> : IRepository<User>
{
}

public class GenericRepository<Order> : IRepository<Order>
{
}

You only need a single line to register multiple implementations.

public void ConfigureServices(IServiceCollection services)
{
    // you can register them with any life time like that e.g. Singleton, Transient
    services.AddScoped(typeof(IRepository<>), typeof(GenericRepository<>));
}

I hope this helps

Answer 2

I also found you can configure your OracleDbContext(s) like this in Configure Services:

services.AddEntityFrameworkOracle()
  .AddDbContext<OracleDbContext>(option => option.UseOracle(Configuration["Data:OracleDbConnection"]), ServiceLifetime.Scoped)
  .AddDbContext<AppsDbContext>(option => option.UseOracle(Configuration["Data:AppsbConnection"]), ServiceLifetime.Scoped);