Hashtable with MultiDimensional Key in C#

Question

I\'m basically looking for a way to access a hashtable value using a two-dimensional typed key in c#.

Eventually I would be able to do something like this

Answer 1

I would suggest that you create a small custom class exposing the bool and int properties, and override its GetHashCode and Equals methods, then use this as the key.

Answer 2

Could you use a Dictionary<KeyValuePair<int,bool>,int>?

Answer 3

I think a better approach is to encapsulate the many fields of your multi-dimensional key into a class / struct. For example

struct Key {
  public readonly int Dimension1;
  public readonly bool Dimension2;
  public Key(int p1, bool p2) {
    Dimension1 = p1;
    Dimension2 = p2;
  }
  // Equals and GetHashCode ommitted
}

Now you can create and use a normal HashTable and use this wrapper as a Key.

Answer 4

I think the easiest way to do it now is to use Tupple.Create and ValueTuple.Create:

> var k1 =  Tuple.Create("test", int.MinValue, DateTime.MinValue, double.MinValue);
> var k2 = Tuple.Create("test", int.MinValue, DateTime.MinValue, double.MinValue);
> var dict = new Dictionary<object, object>();
> dict.Add(k1, "item");
> dict.Add(k2, "item");
An item with the same key has already been added....
> dict[k1] == dict[k2]
true

or use new c#7 tuple syntax to create tuple-keys:

var k = (item1: "value1", item2: 123);