using System;

using System.Collections.Generic;

using System.Collections;

using System.Linq;                  

​

public class Program

{

    public static void Main()

    {

        var coisa1 = new MyClass3

        {

            MyProperty1 = "Valor Original 1",

            MyProperty2 = new MyClass1

            {

                MyProperty = "Valor Original 2"

            },

            MyProperty3 = new List<MyClass2> 

            {

                new MyClass2 

                {

                    MyProperty = "Valor Original 3"

                }

            }

        };

​

        Console.WriteLine("--- Valores Originais ---");

        Console.WriteLine(coisa1.MyProperty1);

        Console.WriteLine(coisa1.MyProperty2.MyProperty);

        Console.WriteLine(coisa1.MyProperty3.First().MyProperty);

​

        Console.WriteLine();

​

        coisa1.Coise();

​

​

        Console.WriteLine("--- Novos Valores ---");

        Console.WriteLine(coisa1.MyProperty1);

        Console.WriteLine(coisa1.MyProperty2.MyProperty);

        Console.WriteLine(coisa1.MyProperty3.First().MyProperty);

​

    }

}

​

public static class CoisableExt

{

    public static void Coise(this Coisable coisableClass) 

    {

        foreach (var propertyInfo in coisableClass.GetType().GetProperties())

        {

            if(typeof(string).IsAssignableFrom(propertyInfo.PropertyType))

            {

                var propValue = propertyInfo.GetValue(coisableClass, null).ToString();

                propValue = "Novo Valor";

                propertyInfo.SetValue(coisableClass, propValue, null);

            }

            else if(typeof(Coisable).IsAssignableFrom(propertyInfo.PropertyType))

            {

                var classPropValue = propertyInfo.GetValue(coisableClass, null) as Coisable;

                classPropValue.Coise();

            }

            else if (typeof(IEnumerable<Coisable>).IsAssignableFrom(propertyInfo.PropertyType))

            {                   

                var classPropValueList = (propertyInfo.GetValue(coisableClass, null) as IEnumerable<Coisable>)?.ToList() ?? default(List<Coisable>);

                if(classPropValueList != null && classPropValueList.Any())

                {

                    classPropValueList.ForEach(classPropValueItem => 

                                               {

                                                   classPropValueItem.Coise();

                                               });

                }

            }

        }

    }

}

​

public class Coisable { }

​

public class MyClass1 : Coisable

{

    public string MyProperty { get; set; }

}

​

public class MyClass2 : Coisable

{

    public string MyProperty { get; set; }

}

​

public class MyClass3 : Coisable

{

    public string MyProperty1 { get; set; }

    public MyClass1 MyProperty2 { get; set; }

    public List<MyClass2> MyProperty3 { get; set; }

}