How do I correctly use Unity to pass a ConnectionString to my repository classes?

Question

I\'ve literally just started using the Unity Application Blocks Dependency Injection library from Microsoft, and I\'ve come unstuck.

This is my IoC class that\'ll ha

Answer 1

I didnt use Unity but I have used configuration objects in these situations. For example you can write your code like this

class Configuration:IRepositoryConfiguration,IMailConfiguration
{
    private string connectionString;

    //IRepository configurations
    public string ConnectionString
    {
        //read connection string from somewhere
        get { return connectionString; }
    }

    //EMail configurations
    public string Smtp
    {
        get { return smpt; }
    }

}

interface IRepositoryConfiguration
{
    string ConnectionString { get;}
}



public abstract class Repository
    {
        public Repository(IRepositoryConfiguration configuration)
        {
            _connectionString = configuration.ConnectionString;
        }

        public virtual string ConnectionString
        {
            get { return _connectionString; }
        }
        private readonly string _connectionString;
    }

So you can register IRepositoryConfiguration and Unity will resolve your configuration objects. Also you can add extra parameters in this approach easily.

Update

I think it is ok to have a constructor that accepts IRepositoryConfiguration object in your concrete classes(abstract repository and MovementRepository). Becase they are implementations details and concrete implementations of IMovementRepository.so they need to know connection string.

Setter or Constructor Injection

I prefer constructor injection over setter injection. I think constructor injection leads more discoverable APIs. in Constructor injection as soon as when you want to instantiate object, you see what an object needs to work but in Setter injection you must learn which property to set to use API. For detailed information you can read Constructor ve Setter Injection