C# Interface implementation

Buford T Justice

So, in college this week we're doing the repository pattern, and we've been given an assignment as follows: (well one part of it): Note, there's been little emphasis on interfaces lately.

Create a repository interface with basic crud methods - IRepo and for the sake of an argument this interface contains a delete method.

Create two other interfaces to represent two different tables (say car and part) and implement IRepo, say called ICar and IPart

Create a DualModel Repository, say CarsAndParts Class that implements both ICar and IPart.

I've done this, and explicitly implemented say the delete method, both of which look like:

  void IRepository<Car>.DeleteItem(int itemID)
        {
            Car item = _context.Cars.Where(p => p.ID == itemID).FirstOrDefault();
            _context.Cars.Remove(item);
        }

        void IRepository<Part>.DeleteItem(int itemID)
        {
            Supplier item = _context.Part.Where(p => p.ID == itemID).FirstOrDefault();
            _context.Part.Remove(item);
        }

However, in my controller when I've instantiated this class I can't get access to these methods. Am I missing something obvious here or what's the story

crazy eyes

Should the method not use the public access modifier

e.g
void IRepository<Part>.DeleteItem(int itemID)
{
Supplier item = _context.Part.Where(p => p.ID == itemID).FirstOrDefault();
_context.Part.Remove(item);
}

should be

public void IRepository<Part>.DeleteItem(int itemID)
{
Supplier item = _context.Part.Where(p => p.ID == itemID).FirstOrDefault();
_context.Part.Remove(item);
}

Buford T Justice

The compiler complains that the modifier public is not valid for this item.

Dubba

Could it be that your Controller doesn't know if it's a Car or a Part object is required?

https://stackoverflow.com/a/2669140

dazberry

Because you've had to implemented the interface explicitly, things work slightly differently. The members are not accessible through their qualified names so are essentially private, BUT because they can be accessed via their interfaces they are then public.

So CarsAndParts might appear to have no methods but:

CarsAndParts cp = new CarsAndParts();
ICar car = cp;
car.DeleteItem(0); <-- is valid

IParts parts = cp;
parts.DeleteItem(0); <-- is also valid

D.