Question

Google Guava provides nice helpers to implement equals and hashCode like the following example demonstrates:

public int hashCode() {
  return Objects.hashCode(lastName, firstName, gender);
}

Is there a similar library for Microsoft .NET?

Answer 1

I don’t see why you’d need one. If you want to create a hash-code based on the default GetHashCode for 3 different items, then just use:

Tuple.Create(lastName, firstName, gender).GetHashCode()

That’ll boil down to the equivalent of:

int h1 = lastName.GetHashCode();
int h2 = firstName.GetHashCode();
int h3 = gender.GetHashCode();
return (((h1 << 5) + h1) ^ (((h2 << 5) + h2) ^ h3));

Which is pretty reasonable for such a general-purpose combination.

Likewise:

Tuple.Create(lastName, firstName, gender).Equals(Tuple.Create(lastName2, firstName2, gender2))

Would boil down to the equivalent of calling:

return ((lastName == null && lastName2 == null) || (lastName != null && lastName.Equals(lastName2)))
  && ((firstName == null && firstName2 == null) || (firstName != null && firstName.Equals(lastName2)))
  && ((gender == null && gender2 == null) || (gender != null && gender.Equals(lastName2)));

Again, about as good as you could expect.