Use IMarkupExtension together with StringFormat

I'm using the TranslateExtension from Xamarin. Is it possible to add a StringFormat to the call?

Currently, I have

<Label Text="{i18n:Translate User}" />

but I would need something like this

<Label Text="{i18n:Translate User, StringFormat='{0}:'}" />

If I do the latter, I get

Xamarin.Forms.Xaml.XamlParseException: Cannot assign property "StringFormat": Property does not exists, or is not assignable, or mismatching type between value and property

I know I could add another translation with a colon, but it would be nice to have a different option.

You can add a parameter property to TranslateExtension.

My TranslateExtension looks like this. You can take the Parameter parts and add it to the one from the Xamarin sample.

[ContentProperty("Text")]
public class TranslateExtension : IMarkupExtension
{
    public string Text { get; set; }
    public string Parameter { get; set; }

    object IMarkupExtension.ProvideValue(IServiceProvider serviceProvider)
    {
        try
        {
            if (Text == null)
                return null;

            var culture = new CultureInfo(CultureHelper.CurrentIsoLanguage);

            var result = LocalizationResources.ResourceManager.GetString(Text, culture);

            if (string.IsNullOrWhiteSpace(Parameter))
            {
                return string.IsNullOrWhiteSpace(result) ? "__TRANSLATE__" : result;
            }

            return string.IsNullOrWhiteSpace(result) ? "__TRANSLATE__" : string.Format(result, Parameter);
        }
        catch (Exception ex)
        {
            TinyInsights.TrackErrorAsync(ex);
            return "__TRANSLATE__";
        }
    }
}