Question

I have an Interface like this:

namespace QuickRoutes.Model.Utilities
{
    public interface IRoutesManager
    {
        bool ImportRoute(Stream inputStream, string fileName);
        List<Route> GetAllRoutes();
        List<Route> GetAllRoutesForDate(DateTime from, DateTime to);
        void DeleteRoute(string routeName);
        void DeleteAllRoutes();

    }
}

and I want to access to i.e ImportRoute function from my Form but I cant access to this Function and an error occured like this:
cannot create an instance of the abstract class or interface
How can I access to these functions?

Answer 1

You need to have an implementation of the interface which defines the actual behaviour. The interface itself only declares the members – as you can see, there’s no code there to say what to do.

Your Form can either create an instance of some implementation, or be given it – quite possibly only as an IRoutesManager, so that the form itself doesn’t need to care about which implementation it’s using.