MyComparer

Class to allow you to compare objects based on custom selectors.

Given a class Foo that you can't edit:

public class Foo
{
    public int Bar { get; set; }
    public float Baz { get; set; }
}

It lets you say

Foo foo1 = GetFoo1();
Foo foo2 = GetFoo2();

IEqualityComparer<Foo> comparer = MyComparer<Foo>.On(f => f.Bar).And(f => f.Baz);
comparer.Equals(foo1, foo2); //returns true iff Bar is equal on both objects *and* Baz is equal on both objects

Or:

List<Foo> foos = GetFoos();
var uniqueFoos = foos.ToHashset(MyComparer<Foo>.On(f => f.Bar).And(f => f.Baz));