System.FormattableString.GetArguments C# (CSharp) Méthode

        public abstract object[] GetArguments();
        public abstract object GetArgument(int index);

 private string ToGerman(FormattableString src)
 {
     return string.Format(
         CultureInfo.CreateSpecificCulture("de-de"),
         src.Format,
         src.GetArguments());
 }