public class UserController
{
    private DatabaseEntity DatabaseModel = new DatabaseEntity();

    public List<UserModelDataTransferObject> GetUsers()
    {
        List<UserModelDataTransferObject> Users = new List<UserModelDataTransferObject>();

        var list = from user in DatabaseModel.User
                   join userRole in DatabaseModel.UserRole on user.UserID equals userRole.UserID
                   join role in DatabaseModel.Role on userRole.UserID equals role.RoleID
                   select new
                   {
                       user.UserID,
                       user.UserName,
                       user.UserPassword,
                       userRole.RoleID,
                       role.RoleName
                   };

        foreach (var elem in list)
        {
            Users.Add(new UserModelDataTransferObject()
            {
                UserID = elem.UserID,
                UserName = elem.UserName,
                UserPassword = elem.UserPassword,
                RoleID = elem.RoleID,
                RoleName = elem.RoleName
            });
        }

        return Users;
    }

}