How can I inherit from ArrayList<MyClass>?

Question

I want to inherit from some kind of array/vector/list class so that I can add just one extra specialized method to it.... something like this:

public class SpacesArray : ArrayList<Space>
{
    public Space this[Color c, int i]
    {
        get
        {
            return this[c == Color.White ? i : this.Count - i - 1];
        }
        set
        {
            this[c == Color.White ? i : this.Count - i - 1] = value;
        }
    }
}

But the compiler won't let me. Says

The non-generic type 'System.Collections.ArrayList' cannot be used with type arguments

How can I resolve this?

Answer 1

ArrayList is not generic. Use List<Space> from System.Collections.Generic.

Answer 2

There is no ArrayList<T>. List<T> works rather well instead.

public class SpacesArray : List<Space>
{
    public Space this[Color c, int i]
    {
        get
        {
            return this[c == Color.White ? i : this.Count - i - 1];
        }
        set
        {
            this[c == Color.White ? i : this.Count - i - 1] = value;
        }
    }
}