// TODO correct exception
        public void AddUser(User user)
        {
            try
            {
                ServiceReference.Service1Client server = new ServiceReference.Service1Client();

                ServiceReference.UserDto userToSend = new ServiceReference.UserDto();
                userToSend.Login    = user.Login;
                userToSend.Password = EncodePasswordToBase64(user.Password);
                userToSend.Name     = user.Name;
                userToSend.Surname  = user.Surname;
                userToSend.Email    = user.Email;
                server.RegisterUser(userToSend);
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine(ex);
            }
        }
        // TODO correct exception
        public User GetUserByLoginAndPassword(string login, string password)
        {
            try
            {
                ServiceReference.Service1Client server = new ServiceReference.Service1Client();

                ServiceReference.UserCredentialsDto cred = new ServiceReference.UserCredentialsDto();
                cred.Login    = login;
                cred.Password = EncodePasswordToBase64(password);

                ServiceReference.UserDto findedUser = server.CheckCredentials(cred);

                User user = new User(findedUser.Name, findedUser.Surname, findedUser.Login, password,
                                     findedUser.Email);

                return(user);
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine(ex);
                return(null);
            }
        }