ValueObject Base Class

ValueObject.cs

 public abstract class ValueObject<T> : IEquatable<T> where T : ValueObject<T>
    {
        private List<PropertyInfo> Properties { get; }

        protected ValueObject()
        {
            Properties = new List<PropertyInfo>();
        }

        public override Boolean Equals(object obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            if (obj.GetType() != GetType()) return false;

            return Equals(obj as T);
        }

        public bool Equals(T other)
        {
            if (ReferenceEquals(null, other)) return false;
            if (ReferenceEquals(this, other)) return true;

            foreach (var property in Properties)
            {
                var myValue = property.GetValue(this, null);
                var otherValue = property.GetValue(other, null);

                if (null == myValue || null == otherValue) return false;
                if (false == myValue.Equals(otherValue)) return false;
            }

            return true;
        }

        public override int GetHashCode()
        {
            var hashCode = 36;
            foreach (var property in Properties)
            {
                var propertyValue = property.GetValue(this, null);
                if (null == propertyValue)
                    continue;

                hashCode = hashCode ^ propertyValue.GetHashCode();
            }

            return hashCode;
        }

        public override string ToString()
        {
            var stringBuilder = new StringBuilder();
            foreach (var property in Properties)
            {
                var propertyValue = property.GetValue(this, null);
                if (null == propertyValue)
                    continue;

                stringBuilder.Append(propertyValue.ToString());
            }

            return stringBuilder.ToString();
        }

        protected void RegisterProperty(Expression<Func<T, object>> expression)
        {
            if (expression == null) throw new ArgumentNullException(nameof(expression));

            MemberExpression memberExpression;
            if (ExpressionType.Convert == expression.Body.NodeType)
            {
                var body = (UnaryExpression)expression.Body;
                memberExpression = body.Operand as MemberExpression;
            }
            else
            {
                memberExpression = expression.Body as MemberExpression;
            }

            if (null == memberExpression)
            {
                throw new InvalidOperationException("InvalidMemberExpression");
            }

            Properties.Add(memberExpression.Member as PropertyInfo);
        }
        public static bool operator ==(ValueObject<T> x, ValueObject<T> y)
        {
            return x.Equals(y);
        }

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

protected void RegisterProperty(Expression<Func<T, object>> expression)

@DavidBrower quick question: where/how is this method used please?