Question

I’m trying to implement DI in a class, but I’m not sure that my design is appropriate.

The relevent code in the class I want to add DI to

class DoerValidation 
{
   public DoerValidation()
   {
       compileData();
   }

   private void compileData()
   {
       doersActive = Doer.GetActiveDoers();
       //...
   }
}

And in my Doer class

public partial class Doer
{
   private static readonly DoerRepository repository = new DoerRepository();

   public static IEnumerable<Doer> GetActiveDoers()
   {
       return repository.Doers.Where(c => c.Person.IsActive);
   }
}

I just don’t get how I could implement DI in this situation. Maybe the GetActiveDoers method is bad design? Where would you put this method otherwise?

Would it be a good practice to start adding new methods directly in the repository? Some people told me it should stay clean so it implements only this

public interface IDoerRepository
{
    IQueryable<Doer> Doers { get; }
    void SaveDoer(Doer doer);
    void DeleteDoer(Doer doer);
}

Answer 1

It sounds like you need to inject the DoerRepository into DoerValidation basically – pass it into the constructor.

Both the GetActiveDoers and the static variable go against the principles of DI, IMO.