Question

Are there any good practices to follow when designing a model/ViewModel to represent data in an app that will view/edit that data in multiple languages? Our top-level class–let’s call it Course–contains several collection properties, say Books and TopicsCovered, which each might have a collection property among its data. What kind of class structure should I implement to hold the data for certain properties in multiple languages?

For example, the data needs to represent course1.Books.First().Title in different languages, and course1.TopicsCovered.First().Name in different languages. We want a app that can edit any of the data for one given course in any of the available languages–as well as edit non-language-specific data, perhaps the Author of a Book (i.e. course1.Books.First().Author). We are having trouble figuring out how best to set up the model to enable binding in the XAML view.

For example, do we replace (in the single-language model) each String with a collection of LanguageSpecificString instances? So to get the Title in the current language:

course1.Books.First().Title.Where(lss => lss.Language==CurrentLanguage).SingleOrDefault()

If we do that, we cannot easily bind to any value in one given language, only to the collection of language values such as in an ItemsControl.

<TextBox Text={Binding Title.???} />  <!-- no way to bind to the current language title -->

Do we replace the top-level Course class with a collection of language-specific Courses? So to get the title in the current language:

course1.GetLanguage(CurrentLanguage).Books.First().Title

If we do that, we can only easily work with one language at a time; we might want a view to show one language and let the user edit the other.

<TextBox Text={Binding Title} />  <!-- good -->
<TextBlock Text={Binding ??? } />  <!-- no way to bind to the other language's title-->

Also, that has the disadvantage of not representing language-neutral data as such; every property (such as Author) would seem to be in multiple languages. Even non-string properties would be in multiple languages.

Is there an option in between those two? Is there another way that we aren’t thinking of?

I realize this is somewhat vague, but it would seem to be a somewhat common problem to design for.

Note: This is not a question about providing a multilingual UI, but rather about actually editing multi-language data in a flexible way.

Edit: so the question is how should we model the classes? Something like this:

Class Course { 
    ObservableCollection<Book> Books
    ObservableCollection<Topic> TopicsCovered
}
Class Book {
    ObservableCollection<LanguageSpecificString> Title
    String Author
}
Class Topic {
    ObservableCollection<LanguageSpecificString> Name
}
Class LanguageSpecificString {
    String LanguageCode
    String Value
}

Or should it be something like:

Class MultilingualCourse { 
    Course GetLanguage(string languageCode)
}
Class Course { 
    ObservableCollection<Book> Books
    ObservableCollection<Topic> TopicsCovered
}
Class Book {
    String Title
    String Author
}
Class Topic {
    String Name
}

Or something else altogether?

Answer 1

We’ve decided to go simpler than these answers and just replace each string that is translatable with a Dictionary<string, string> (language, value). Of course, we may wish to Dictionary<CultureInfo, string> in the future. This is close to my first answer in the original post.