using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var docs = new List<Doc>()

        {

            new Doc(1, "C:\\Files\\A.txt"),

            new Doc(2, "C:\\Files\\B.txt"),

            new Doc(3, "C:\\Files\\C.txt"),

        };

        var users = new List<User>()

        {

            new User(1, "Adam"),

            new User(2, "Benny"),

            new User(3, "Charlie"),

        };

        var dus = new List<Doc_User>()

        {

            new Doc_User(1,1),

            new Doc_User(1,2),

            new Doc_User(2,1),

            new Doc_User(2,2),

            new Doc_User(2,3)

        };

        var db = new DB() { Docs = docs, Users = users, DU = dus };

        var model = (from d in db.Docs

                     join du in db.DU on d.Id equals du.DocId

                     join u in db.Users on du.UserId equals u.Id

                     select new DataModel() { DocPath = d.Path, UserName = u.Name }).ToList();

        foreach(var item in model)

        {

            Console.WriteLine(item.DocPath + " | " + item.UserName);    

        }

    }

}

​

public class DB

{

    public List<Doc> Docs {get; set;}

    public List<User> Users {get; set;}

    public List<Doc_User> DU {get; set;}

}

​

public class Doc

{

    public Doc(int id, string path)

    {

        Id = id;

        Path = path;

    }

    public int Id {get; set;}

    public string Path {get; set;}  

}

​

public class User

{

    public User(int id, string name)

    {

        Id = id;

        Name = name;

    }

    public int Id {get; set;}

    public string Name {get; set;}  

}

public class Doc_User

{

    public Doc_User(int idD, int idU)

    {

        DocId = idD;

        UserId = idU;

    }

    public int DocId {get; set;}

    public int UserId {get;set;}

}

​

public class DataModel

{

    public string DocPath {get; set;}

    public string UserName {get; set;}

}

​