public override Task <bool> ExecuteInternal(object parameter)
        {
            var cred = new Views.Credentials("Storage account name:",
                                             "Storage account key:",
                                             "Connect to Storage account",
                                             Preferences.Instance.LoginName,
                                             Preferences.Instance.AuthKey);

            if (cred.ShowDialog() == true)
            {
                Vm.Login(cred.ShortField.Text, cred.LongField.Text);
                Preferences.Instance.LoginName = cred.ShortField.Text;
                Preferences.Instance.AuthKey   = cred.LongField.Text;
                return(True);
            }
            return(False);
        }