private async void Login_Button_Click(object sender, RoutedEventArgs e)
        {
            var errorMessage    = string.Empty;
            var loginParameters = GetLoginParametes();

            if (IsValid(loginParameters, ref errorMessage))
            {
                Login_Button.IsEnabled = false;

                var loginResponse = await _loginService.TryLogin(loginParameters);

                if (loginResponse.Success)
                {
                    LoginLogoutManager.Singleton.CurrentUser = UserData_VM.FromLoginResponse(loginResponse, loginParameters);
                    new MainWindow().Show();
                    ((Parent as Grid).Parent as LoginWindow).Close();
                }
                else
                {
                    MessageBox.Show(
                        "Login failed!\r\n" +
                        "Most probably - wrong e-mail or password... but also might be server problem.\r\n" +
                        "Retry once again!");
                }

                Login_Button.IsEnabled = true;
            }
            else
            {
                MessageBox.Show(errorMessage);
            }

            e.Handled = true;
        }