Explicit implementation of property through an abstract class in C#

Question

Here's what I am trying to do:

At the top sits an interface:

interface IHasPosition
    {
        Position Position
        {
            get;
        }
    }

next up, we have an abstract class:

abstract class Person : IHasPosition
    {
        public abstract Position Position
        {
            get;
        }
    }

Finally, I extend Person:

class Instructor : Person
    {
        public override Position Position
        {
            get { return new Position(1, 1); }
        }
    }

This compiles just fine. However, I seem to be unable to explicitly define the property Position. Something like this:

class Instructor : Person
    {
        public override Position IHasPosition.Position
        {
            get { return new Position(1, 1); }
        }
    }

This fails to compile:

Error   1   'ConsoleApplication3.Instructor.IHasPosition.Position': virtual or abstract members cannot be private
Error   3   The modifier 'override' is not valid for this item
Error   2   The modifier 'public' is not valid for this item

Why do you want to explicitly implement the interface's property? — Alireza
– Alireza, Commented Oct 4, 2013 at 13:36
The modifier 'public' is not valid for this item - you are trying to implement it explicitly; The modifier 'override' is not valid for this item - again related to first statement — terrybozzio
– terrybozzio, Commented Oct 4, 2013 at 13:43
what are you trying to do exactly?i mean why abstract implementation on base class and private in derived?or do you want public in derived? — terrybozzio
– terrybozzio, Commented Oct 4, 2013 at 16:00

Jodrell · Accepted Answer · 2013-10-04 15:55:51Z

3

Instructor is inheriting Person and Instructor.Position is overriding Person.Position.

Since Person.Position already implements IHasPosition.Postion, so does Instructor.Position.

Instructor is a Person is a IHasPosition.

Explicit implementation of the interface IHasPosition.Position on Instrcutor is unnesscessary and, would be misleading.

Lets possit that you do explicitly implement the interface that has already been inherited. On the override it is superfluous, and illegal because its public, on another member it creates an ambiguity.

edited Oct 4, 2013 at 15:55

answered Oct 4, 2013 at 13:35

Jodrell

35.8k6 gold badges94 silver badges131 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Dmitrii Bychenko · Accepted Answer · 2013-10-04 13:59:08Z

1

There's a syntax error in your code: explicit interface implementation can't be public. Technically, you can put it like that:

   class Instructor: Person {
     // From Person abstract class
     public override Position Position 
     {
       get { return new Position(1, 1); }
     }

     // Explicit interface implementation
     Position IHasPosition.Position 
     {
       get { ... }
     }
   }

But as Jodrell said, it's a very bad style.

answered Oct 4, 2013 at 13:59

Dmitrii Bychenko

188k20 gold badges178 silver badges231 bronze badges

2 Comments

Jodrell Over a year ago

+1 for showing you can actually do it. (-1 to anybody who actually does.)

Henry Henrinson Over a year ago

That still doesn't seem to work. It complains about the containing type not implementing IHasPosition: Error 'ConsoleApplication3.Instructor.IHasPosition.Position': containing type does not implement interface 'ConsoleApplication3.IHasPosition'

Collectives™ on Stack Overflow

Explicit implementation of property through an abstract class in C#

2 Answers 2

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related