Question

In C#, the Dictionary class takes a single key and maps it to a single value. I’m looking for something similar, where I can pass in an ordered tuple and get a single value — without wrapping it in a class.

Here’s a pretty hypothetical example of what I want (with buttons, instead of some 2D map tile). Currently, I can do this:

Dictionary<int, Button> buttons = new Dictionary<int, Button>();

If I want to use each button’s coordinates as the key, I can do this:

Dictionary<Point, Button> buttons = new Dictionary<Point, Button>();
buttons[new Point(b.X, b.Y)] = b;

What I would like to do is this

Dictionary<int, int, Button> buttons = new Dictionary<int, int, Button>();
buttons[b.X, b.Y] = b;

Again, it’s a trivial case with a known work-around. But I just find it annoying that I have to create a new placeholder class (struct?) with each set of parameters that I want to use as a key.

Is this somehow possible?

Answer 1

public class TupleDictionary<T1, T2, TValue> : Dictionary<Tuple<T1,T2>,TValue>
{
    public TValue this[T1 t1, T2 t2]
    {
        get { return this[new Tuple<T1, T2>(t1, t2)]; }
        set { this[new Tuple<T1, T2>(t1,t2)] = value; }
    }

    public void Add(T1 t1, T2 t2, TValue value)
    {
        Add(new Tuple<T1, T2>(t1, t2), value);
    }

    public void Remove(T1 t1, T2 t2)
    {
        Remove(new Tuple<T1, T2>(t1, t2));
    }

    public bool ContainsKey(T1 t1, T2 t2)
    {
        return ContainsKey(new Tuple<T1, T2>(t1, t2));
    }

    public bool TryGetValue(T1 t1, T2 t2, out TValue value)
    {
        return TryGetValue(new Tuple<T1, T2>(t1, t2), out value);
    }
}