[Program.cs]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace TestConsole
{
    public class Program
    {
        public static string TestString = "Im a test!";
        static void Main(string[] args)
        {
            Console.WriteLine(TestString);
            Console.ReadLine();
        }
    }
}


[SFTP.cs]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace TestConsole
{
    class SFTP
    {
       //Hier geht kein TestString
    }
}