[Enhancement] Localization manager with more than one resource manager

[WebDucer]

Summary

Currently the localization manager (singleton) can be initialized only with one resource manager. This is often not enough.

We ceurrently use own implementation for this purpose, that accept a list of resource managers (form common library, different app modules).

API Changes

Non breaking changes:

XamarinCommunityToolkit/src/CommunityToolkit/Xamarin.CommunityToolkit/Helpers/LocalizationResourceManager.shared.cs

Line 16 in f62c078

ResourceManager resourceManager;

ResourceManager[] resourceManagers = new ResourceManager[0];

XamarinCommunityToolkit/src/CommunityToolkit/Xamarin.CommunityToolkit/Helpers/LocalizationResourceManager.shared.cs

Lines 25 to 32 in f62c078

	public void Init(ResourceManager resource) =>
	resourceManager = resource;
	public void Init(ResourceManager resource, CultureInfo initialCulture)
	{
	resourceManager = resource;
	currentCulture = initialCulture;
	}

public void Init(params ResourceManager[] resources) =>
    resourceManagers = resources;

public void Init(ResourceManager resource, CultureInfo initialCulture)=>
    Init(initialCulture, resource);

public void Init(CultureInfo initialCulture, params ResourceManager[] resources)
{
    resourceManagers = resources;
    currentCulture = initialCulture;
}

XamarinCommunityToolkit/src/CommunityToolkit/Xamarin.CommunityToolkit/Helpers/LocalizationResourceManager.shared.cs

Lines 34 to 35 in f62c078

	public string GetValue(string text) =>
	resourceManager.GetString(text, CurrentCulture);

public string GetValue(string text)
{
    string translated = null;

    foreach (var rm in resourceManagers)
    {
        translated = rm.GetString(text, CurrentCulture);
        if (translated != null)
        {
            break;
        }
    }

    return translated;
    // Or as LINQ
    // return resourceManagers.Select(s => s.GetString(text, CurrentCulture))
    //    .FirstOrDefault(f => f != null);
}

Intended Use Case

Usage with more than one resource manager.

Who Will Do The Work?

• I am willing to take this on myself
• Just putting this out there for someone to pick up

[AmrAlSayed0]

I don't think this would work correctly in case of multiple string resources with the same name but in different resource files. What I suggest it modify the LocalizationResourceManager to take either one ResourceManager or multiple and modify the current GetValue to check if there is only one ResourceManager registered, otherwise throw and exception. Also, add another GetValue that takes an extra parameter of ResourceManager which the method will use.

The TranslateExtension can be modified to take an optional reference to the ResourceManager it should use. If it is not set then it should assume that there is only one ResourceManager and use the one parameter GetValue method

[TheCodeTraveler]

Thanks Eugen!

Before approving this, I'm going to play around with LocalizationResourceManager to see if there's a way we can utilize RESX to do this for us.

If we can leverage RESX, we might be able to save ourselves a bunch code 🤞

[WebDucer]

@AmrAlSayed0 The possibility of ovveriding translations, is feature that we already use. E.g. we override some translations from core library in our RESX in the application. During the initialization we put the most relevant resource manager first (Application) and least relevant as last (Core).

[WebDucer]

@brminnick This would be fine. I also miss now the possibility to set the culture on all resources in one place. Now we need to set the culture to all resource managers used in the application, if user set new culture.

[maxkoshevoi]

@WebDucer In your implementation you are searching through all resource managers until you find string with needed key.
So each key is unique across all resource managers? I don't think this is the case for all users that use several resource managers.
In your use case what is the point of having multiple resource managers if you are searching though all of them anyway?

Could you please take a look at #1047 and see if that implementation suits your needs?

[WebDucer]

@maxkoshevoi No, the key is not unique. #1047 could match our needs.

[maxkoshevoi]

@WebDucer Thank you for validating #1047

If key is not unique, then LRM would always return first value it finds (and never any others). How do you deal with that in your project? I don't use multiple resource managers, so would be happy to hear how people deal with them in the real world.

Benefits of your approach is that you don't need to provide TranslateExtesnion with resource manager every time you use it, but in #1047 you do (except when you want to use default one).

[WebDucer]

@maxkoshevoi We explicitly use the possibility for everriding translations.

To prevent unwanted overriding, we use prefixes for translation keys, dependent on origin RESX project, e.g.:

• Common library
  • COM_ButtonCancel
  • COM_ButtonAccept
  • COM_LabelCompany
• App module 1
  • MODA_LabelServer
  • MODA_LabelUrl
  • COM_LabelCompanny (override the common library translation)

During the initialization of LRM we add the most relevant manager (mostly of the App) as first, and least relevant last (libraries).

In C# code of the App we explicitly use the resource managers directly (e.g.: CommonLocalization.COM_LabelCompany or AppLocalization.COM_LabelCompany). The multi registration we use in XAML extension (and in libraries code over localization service). So we are always able to override translations in libraries.

The overrides are mostly used, if we have more languages, that the library provides (most of our app has 3 languages, but some are translated in 8).