using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        List<int?> result= new List<int?>{

            1,2,3,null,4,5,6,7,8,9

        };

        Console.WriteLine("Prueba de ValidateIntList: {0}", ValidateIntList(result) );

        Console.WriteLine("Prueba de ValidateSam: {0}", ValidateSam(result) );

    }

    public static bool ValidateIntList(List<int?> request)

        {

            bool response = true;

            if (request == null || !request.Any()){

                return false;

            }

            request.ForEach(item =>

            {

                if (item.HasValue && (item.Value <= 0 && response))

                {

                    response = false;

                }

            });

            return response;

        }

    public static bool ValidateSam(List<int?> request)

    {

         if (request == null || !request.Any()){

            return false;

         }

        return request.All(item => item.HasValue && item.Value >= 0 );

    }

}