How can I inherit from ArrayList<MyClass>?

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开发者_JAVA技巧;
        }
    }
}

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?

---

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

---

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;
        }
    }
}

---

You can create a wrapper around ArrayList<T>, which implements IReadOnlyList<T>. Something like:

public class FooImmutableArray<T> : IReadOnlyList<T> {
    private readonly T[] Structure;

    public static FooImmutableArray<T> Create(params T[] elements) {
        return new FooImmutableArray<T>(elements);
    }

    public static FooImmutableArray<T> Create(IEnumerable<T> elements) {
        return new FooImmutableArray<T>(elements);
    }

    public FooImmutableArray() {
        this.Structure = new T[0];
    }

    private FooImmutableArray(params T[] elements) {
        this.Structure = elements.ToArray();
    }

    private FooImmutableArray(IEnumerable<T> elements) {
        this.Structure = elements.ToArray();
    }

    public T this[int index] {
        get { return this.Structure[index]; }
    }

    public IEnumerator<T> GetEnumerator() {
        return this.Structure.AsEnumerable().GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator() {
        return GetEnumerator();
    }

    public int Count { get { return this.Structure.Length; } }

    public int Length { get { return this.Structure.Length; } }
}