Xamarin表单:使用IValueConverter连接主url和剩余url

public class UrlConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        string mainUrl = value as string;
        string remainingUrl = parameter as string;

        if (!string.IsNullOrEmpty(mainUrl) && !string.IsNullOrEmpty(remainingUrl))
        {
            return mainUrl + remainingUrl;
        }

        return string.Empty;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

<Label Text="{Binding MainUrl, Converter={StaticResource UrlConverter}, ConverterParameter={Binding RemainingUrl}}" />