Tuples( or arrays ) as Dictionary keys in C#

by

If you are on .NET 4.0 use a Tuple:

lookup = new Dictionary<Tuple<TypeA, TypeB, TypeC>, string>();

If not you can define a Tuple and use that as the key. The Tuple needs to override GetHashCode, Equals and IEquatable:

struct Tuple<T, U, W> : IEquatable<Tuple<T,U,W>>
{
    readonly T first;
    readonly U second;
    readonly W third;

    public Tuple(T first, U second, W third)
    {
        this.first = first;
        this.second = second;
        this.third = third;
    }

    public T First { get { return first; } }
    public U Second { get { return second; } }
    public W Third { get { return third; } }

    public override int GetHashCode()
    {
        return first.GetHashCode() ^ second.GetHashCode() ^ third.GetHashCode();
    }

    public override bool Equals(object obj)
    {
        if (obj == null || GetType() != obj.GetType())
        {
            return false;
        }
        return Equals((Tuple<T, U, W>)obj);
    }

    public bool Equals(Tuple<T, U, W> other)
    {
        return other.first.Equals(first) && other.second.Equals(second) && other.third.Equals(third);
    }
}

More Related Contents:

  1. .NET HashTable Vs Dictionary – Can the Dictionary be as fast?
  2. Hashtable with MultiDimensional Key in C#
  3. Hashtable to Dictionary syncroot .
  4. How to read lines to dictionary with linQ [closed]
  5. Collection was modified; enumeration operation may not execute
  6. Serialize Class containing Dictionary member
  7. ASP.NET MVC Binding to a dictionary
  8. Get dictionary key by value
  9. What is more efficient: Dictionary TryGetValue or ContainsKey+Item?
  10. How to update the value stored in Dictionary in C#?
  11. What requirement was the tuple designed to solve?
  12. How to easily initialize a list of Tuples?
  13. Modify Struct variable in a Dictionary
  14. Why doesn’t XmlSerializer support Dictionary?
  15. Proper way to initialize a C# dictionary with values
  16. .NET ObservableDictionary
  17. Multi Value Dictionary?
  18. A dictionary object that uses ranges of values for keys
  19. Equivalent of Tuple (.NET 4) for .NET Framework 3.5
  20. Enum to Dictionary in C#
  21. Store Dictionary in application settings
  22. Reverse Sorted Dictionary in .NET
  23. Good way to get the key of the highest value of a Dictionary in C#
  24. How to sort a dictionary by key
  25. C# Convert List to Dictionary
  26. The given key was not present in the dictionary. Which key?
  27. Best way to change dictionary key
  28. C# anonymous object with properties from dictionary
  29. Get the last element in a dictionary?
  30. Map two lists into a dictionary in C#

Leave a Comment