public static class LinqExtensions
{
        public static IEnumerable<T> DistinctBy<T, TResult>(this IEnumerable<T> source, Func<T, TResult> keySelector)
        {
            EqualityComparer<T, TResult> compare = new EqualityComparer<T, TResult>(keySelector);
            return source.Distinct(compare);
        }

        public static IEnumerable<T> ExceptBy<T, TResult>(this IEnumerable<T> first, IEnumerable<T> second, Func<T, TResult> keySelector)
        {
            EqualityComparer<T, TResult> compare = new EqualityComparer<T, TResult>(keySelector);
            return first.Except(second, compare);
        }
 }

    public class EqualityComparer<T, TResult> : IEqualityComparer<T>
    {
        private Func<T, TResult> selector { get; set; }
        public EqualityComparer(Func<T, TResult> selector)
        {
            this.selector = selector;
        }

        public bool Equals(T left, T right)
        {
            bool result = true;
            if (left == null && right == null)
            {
                result = true;
            }
            else if (left == null ^ right == null)
            {
                result = false;
            }
            else
            {
                var leftProp = selector.Invoke(left);
                var rightProp = selector.Invoke(right);
                EqualPropertie(leftProp, rightProp, ref result);
            }
            return result;
        }

        public int GetHashCode(T obj)
        {
            return obj == null ? 0 : obj.ToString().GetHashCode();
        }

        private void EqualPropertie<TObject>(TObject left, TObject right, ref bool result)
        {
            var propertyInfos = left.GetType().GetProperties();
            foreach (var parentItem in propertyInfos)
            {
                if (!result)
                {
                    return;
                }
                var leftProp = parentItem.GetValue(left);
                var rightProp = parentItem.GetValue(right);
                if (parentItem.PropertyType.IsClass && parentItem.PropertyType.Name != "String")
                {
                    EqualPropertie(leftProp, rightProp, ref result);
                }
                else
                {
                    if (leftProp == null && rightProp == null)
                    {
                        result = true;
                    }
                    else if (leftProp == null ^ rightProp == null)
                    {
                        result = false;
                    }
                    else
                    {
                        result = leftProp.Equals(rightProp);
                    }
                }
            }
        }
    }