Xamarin.Forms : How to use localization independent of device language

Question

I am developing a Xamarin.Forms app (portable class library project) with Visual Studio 2013 CE. First I\'m focusing the iOS version.

Now I\'m thinking about how to make

Answer 1

I don't believe you can do this from within your shared PCL project. However, you CAN set the UICulture from within your platform-specific projects. To do this from a useful location (i.e., your Forms app), we must expose this as a service from your platform projects as a dependency.

First, define the interface that describes your culture management "service." This should live in an assembly that is referenced by your platform-specific projects (the shared PCL project will do):

public interface ICultureInfo
{
    System.Globalization.CultureInfo CurrentCulture { get; set; }
    System.Globalization.CultureInfo CurrentUICulture { get; set; }
}

And in each of your platform projects, include a type that implements that interface:

using System;
using Xamarin.Forms;
using System.Threading;

[assembly:Dependency(typeof(YourNamespaceHere.PlatformCultureInfo))]
namespace YourNamespaceHere
{
    public class PlatformCultureInfo : ICultureInfo
    {
        #region ICultureInfo implementation

        public System.Globalization.CultureInfo CurrentCulture {
            get {
                return Thread.CurrentThread.CurrentCulture;
            }
            set {
                Thread.CurrentThread.CurrentCulture = value;
            }
        }

        public System.Globalization.CultureInfo CurrentUICulture {
            get {
                return Thread.CurrentThread.CurrentUICulture;
            }
            set {
                Thread.CurrentThread.CurrentUICulture = value;
            }
        }

        #endregion
    }
}

Then in your forms app, you request an instance of the platform's implementation from the Xamarin Forms DependencyService. (NOTE: Any calls to the DependencyService must happen AFTER a call to Forms.Init())

Once you retrieve it, you can set the current UI culture:

var cultureInfo = Xamarin.Forms.DependencyService.Get();
cultureInfo.CurrentUICulture = new System.Globalization.CultureInfo("fr-FR");

Et voila, any changes to the UI culture will be reflected with any subsequent resource lookups. Note the use of the word "subsequent" - any forms using resource lookups (such as if you're using my handy localization XAML markup extensions) won't reflect the culture change until they are refreshed/reloaded.

In closing, the Xamarin team did a great job duplicating the original resource lookup infrastructure! It just needs a little push to get it into the world of Xamarin Forms.