using System;

using System.Text;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Antrag A = new Antrag();

        A.Anwendungen.Items = new List<string>();

        A.Anwendungen.Items.Add("A");

        A.Anwendungen.Items.Add("B");

        A.Ersteller.Name = "Hans";

        Antrag B = new Antrag();

        B.Passworte.Items = new List<Dictionary<string, string>>();

        B.Passworte.Items.Add("A", "Username");

    }

    public class Antrag{

        public string AntragsDaten(){

            StringBuilder builder = new StringBuilder();

            builder.Append(CatItems(Passworte);

            builder.Append(CatItems(Anwendungen);

            return builder.ToString();

        }

        public string CatItems(Collection Collection){

            StringBuilder builder = new StringBuilder();

            foreach (var Item in Collection.AsEnumerable()){

                builder.Append(Item ?? Item.ToString());

            }

            return builder.ToString();

        public Ersteller Ersteller;

        public Passworte Passworte;

        public Anwendungen Anwendungen;

    }

    public class Ersteller{

        public string Name;

        public string ID;

    }

    public class Passworte{

        public List<Dictionary<string, string>> Items;

    }

    public class Anwendungen{

        public List<string> Items;

    }

}