Any possibility to declare indexers in C# as an abstract member?

Question

As the title states, I would like to declare an indexer object this[int index] in an abstract class as an abstract member.

Is this possible in any way? Is it possible to declare this in an interface too?

Answer 1

Of course:

public abstract class ClassWithAbstractIndexer 
{
    public abstract int this[int index]
    {
        get;
        set;
    }
}

Answer 2

A simple example:

public interface ITest
{
    int this[int index] { get;  }
}

public class Test : ITest
{
    public int this[int index]
    {
        get { ... }
        private set { .... }
    }
}

Several combinations of private/protected/abstract are possible for get and set

Answer 3

You may declare it like this:

internal abstract class Hello
{
  public abstract int Indexer[int index]
  {
      get;
  }
}

Then you'll have the option to override only get or override both get and set.