Value Object

1.cs

public abstract class ValueObject<T>
    where T : ValueObject<T>
{
    public override bool Equals(object obj)
    {
        var valueObject = obj as T;

        if (ReferenceEquals(valueObject, null))
            return false;
            
        if (GetType() != obj.GetType())
            return false;

        return EqualsCore(valueObject);
    }

    protected abstract bool EqualsCore(T other);

    public override int GetHashCode()
    {
        return GetHashCodeCore();
    }

    protected abstract int GetHashCodeCore();

    public static bool operator ==(ValueObject<T> a, ValueObject<T> b)
    {
        if (ReferenceEquals(a, null) && ReferenceEquals(b, null))
            return true;

        if (ReferenceEquals(a, null) || ReferenceEquals(b, null))
            return false;

        return a.Equals(b);
    }

    public static bool operator !=(ValueObject<T> a, ValueObject<T> b)
    {
        return !(a == b);
    }
}

2.cs

public class Address : ValueObject<Address>
{
    public string Street { get; }
    public string City { get; }
    public string ZipCode { get; }

    public Address(string street, string city, string zipCode)
    {
        Street = street;
        City = city;
        ZipCode = zipCode;
    }

    protected override bool EqualsCore(Address other)
    {
        return Street == other.Street
            && City == other.City
            && ZipCode == other.ZipCode;
    }

    protected override int GetHashCodeCore()
    {
        unchecked
        {
            int hashCode = Street.GetHashCode();
            hashCode = (hashCode * 397) ^ City.GetHashCode();
            hashCode = (hashCode * 397) ^ ZipCode.GetHashCode();
            return hashCode;
        }
    }
}

3.cs

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

    public override bool Equals(object obj)
    {
        if (obj == null)
            return false;

        if (GetType() != obj.GetType())
            return false;

        var valueObject = (ValueObject)obj;

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

    public override int GetHashCode()
    {
        return GetEqualityComponents()
            .Aggregate(1, (current, obj) =>
            {
                unchecked
                {
                    return current * 23 + (obj?.GetHashCode() ?? 0);
                }
            });
    }

    public static bool operator ==(ValueObject a, ValueObject b)
    {
        if (ReferenceEquals(a, null) && ReferenceEquals(b, null))
            return true;

        if (ReferenceEquals(a, null) || ReferenceEquals(b, null))
            return false;

        return a.Equals(b);
    }

    public static bool operator !=(ValueObject a, ValueObject b)
    {
        return !(a == b);
    }
}

4.cs

public class Address : ValueObject
{
    public string Street { get; }
    public string City { get; }
    public string ZipCode { get; }

    public Address(string street, string city, string zipCode)
    {
        Street = street;
        City = city;
        ZipCode = zipCode;
    }

    protected override IEnumerable<object> GetEqualityComponents()
    {
        yield return Street;
        yield return City;
        yield return ZipCode;
    }
}

5.cs

protected override IEnumerable<object> GetEqualityComponents()
{
    yield return Street;
    yield return City;
    yield return ZipCode;
}

6.cs

public class Address : ValueObject
{
    public string Street { get; }
    public string City { get; }
    public string ZipCode { get; }
    public List<Tenant> Tenants { get; }

    public Address(string street, string city, string zipCode, List<Tenant> tenants)
    {
        Street = street;
        City = city;
        ZipCode = zipCode;
        Tenants = tenants;
    }

    protected override IEnumerable<object> GetEqualityComponents()
    {
        yield return Street;
        yield return City;
        yield return ZipCode;

        foreach (Tenant tenant in Tenants)
        {
            yield return tenant;
        }
    }
}

7.cs

public class Money : ValueObject
{
    public string Currency { get; }
    public decimal Amount { get; }

    public Money(string currency, decimal amount)
    {
        Currency = currency;
        Amount = amount;
    }

    protected override IEnumerable<object> GetEqualityComponents()
    {
        yield return Currency.ToUpper();
        yield return Math.Round(Amount, 2);
    }
}

8.cs

var money1 = new Money("usd", 2.2222m);

9.cs

var money2 = new Money("USD", 2.22m);