IEqualityComparer<T> delegating work to underlying Func<T, TKey>

gistfile1.cs

public class FuncComparer<T, TKey> : IEqualityComparer<T>
{
  private readonly Func<T, TKey> _func;

	public FuncComparer(Func<T, TKey> func)
	{
		_func = func;
	}

	public bool Equals(T x, T y)
	{
		return _func(x).Equals(_func(y));
	}

	public int GetHashCode(T obj)
	{
		return _func(obj).GetHashCode();
	}
}

// Usage
var results = Enumerable.Range(1, 10).Distinct(new FuncComparer<int, string>(i => i.ToString()));