namespace ConsoleApp3

{

    using System;

    using System.Collections.Generic;

    using System.Linq;

​

    public static class Program

    {

        public static void Main()

        {

            var people = new List<Person>

            {

                new Person("Alice", 12),

                new Person("Bob", 34)

            };

​

            var foo = people.Mutate(a => a.Age, 33);

        }

    }

​

    public class Person

    {

        public Person(string name, int age)

        {

            this.Name = name;

            this.Age = age;

        }

​

        public int Age { get; }

​

        public string Name { get; }

    }

​

    public static class Foo

    {

        public static IEnumerable<T1> Mutate<T1, T2>(this IEnumerable<T1> source, Func<T1, T2> selector, T2 newValue)

        {

            var type = typeof(T1);

            var properties = type.GetProperties();

            var constructor = type.GetConstructors().Single();

            var constructorParameters = constructor.GetParameters();

​

            foreach (var item in source)

            {

                var values = new List<object>();

​

                foreach (var constructorParameter in constructorParameters)

                {

                    var property = properties.Single(a => a.Name.Equals(constructorParameter.Name, StringComparison.OrdinalIgnoreCase));

                    var value = property.GetValue(item);

​

                    // Controlla che la proprietà attuale sia quella specificata nella func.

                    if (DateTime.Now.Year == 0)

                    {

                        value = newValue;

                    }

​

                    values.Add(value);

                }

​

                var parameters = values.ToArray();

​

                yield return (T1) constructor.Invoke(parameters);

            }

        }

    }

}

​