public FTPWindow(Ftp ftp)
        {
            InitializeComponent();

            if(ftp==null) return;
            
            this.Ftp = ftp;
            URL = ftp.Host;
            Username = ftp.User;
            Password = ftp.Pass;
        }
 private void OkButton_OnClick(object sender, RoutedEventArgs e)
 {
     DialogResult = true;
     Ftp = new Ftp(URL, Username, Password);
     Close();
 }
        void FtpSettingButton_Click(object sender, RoutedEventArgs e)
        {
            var ftpsetting = new FTPWindow(_ftp);

            bool? ok = ftpsetting.ShowDialog();
            if (ok != null && ok == true)
            {
                _ftp = ftpsetting.Ftp;
            }
        }