DDD ValueObject

ValueObject.cs

public abstract class ValueObject
{
    protected abstract IEnumerable<object> GetEqualityComponents();

    public override bool Equals(object? other)
    {
        if (other is null || other.GetType() != GetType())
        {
            return false;
        }

        var otherValue = (ValueObject)other;

        return GetEqualityComponents().SequenceEqual(otherValue.GetEqualityComponents());
    }

    public override int GetHashCode()
    {
        var hash = new HashCode();

        foreach (var c in GetEqualityComponents())
        {
            hash.Add(c ?? 0);
        }

        return hash.ToHashCode();
    }

    public static bool operator ==(ValueObject left, ValueObject right)
    {
        if (left is null ^ right is null)
        {
            return false;
        }

        return left is null || left.Equals(right);
    }

    public static bool operator !=(ValueObject left, ValueObject right)
    {
        return !(left == right);
    }
}