GenericComparer<T>

GenericComparer.cs

public class GenericComparer<T> : IComparer<T>
{
	private readonly Func<T, IComparable> _comparer;
	
	private GenericComparer(Func<T, IComparable> comparer)
	{
		_comparer = comparer ?? throw new ArgumentNullException(nameof(comparer));
	}
	
	public static GenericComparer<T> Create(Func<T, IComparable> comparer)
	{
		return new GenericComparer<T>(comparer);
	}
	
	public int Compare(T? x, T? y)
	{
		if (x == null && y == null) return 0;
		if (x == null) return -1;
		if (y == null) return 1;
		return _comparer(x).CompareTo(_comparer(y));
	}
}