ConnectDialogWpf.xaml の相互作用ロジック
Inheritance: System.Windows.Window
        /// <summary>
        /// Creates an instance of PasswordDialog and uses it to obtain the user's password.
        /// </summary>
        /// <returns>Returns the user's password as entered, or null if he/she clicked Cancel.</returns>
        public static string GetVncHost()
        {
            ConnectDialogWpf dialog = new ConnectDialogWpf();

            dialog.VncHostBox.Focus();
            dialog.ShowDialog();


            if (dialog.DialogResult == true)
            {
                return dialog.VncHostBox.Text;
            }
            else
            {
                return null;
            }
        }