Question

I have a scenario using Unity which is a bit confusing… Say I have an AuthenticationService that authenticates users and when successful logs to a text file or database using TextLogger class or DbLogger class respectively. Normally for which ever class I will use in my project I would register appropriately in my module class as below:

public class LoggingModule
{
    IUnityContainer _iocContainer;

    public LoggingModule(IUnityContainer container)
    {
        _iocContainer = container;
    }

    public void Init()
    {
        //Add any logic here to look in a config file, check a property
        //or any other condition to decide which implementation is registered.

        //register the database logger to the ILogger interface
        _iocContainer.RegisterType(typeof(ILogger), typeof(DBLogger));

    }
}

And this will be injected into the constructor of my Authentication Service. However if I wanted to use both loggers at different points in my application, first do I Register both types in my Init method, i.e. the TextLogger and DBLogger?
Second, how does my container know which type to Resolve?

Please help….

Answer 1

Register your both types into container with a name, i.e.;

container.RegisterType<ILogger, DBLogger>("DBLogger");
container.RegisterType<ILogger, TextLogger>("TextLogger");

and resolve your types using the name parameter, i.e.;

var logger = container.Resolve<ILogger>("DBLogger");