What is the proper way to bind a dynamic value from a language file?

Question

I have a view model which has the name of an entry in my language resource file.
I tried to bind this value directly to the x:Uid attribute of the TextBlock in my XAML, but got a XAML error.

To get around this limitation I though about changing the property to return the value from the language file, but was concerned that doing so might not be a valid MVVM solution.
I also thought about creating a converter to set the text.

Way that does not work:

<StackPanel Orientation="Horizontal">
    <Image Margin="0,0,20,0" Source="{Binding IconPath}" />
    <TextBlock x:Uid="{Binding LanguageResourceName}" />
</StackPanel>

The view model I am binding to:

class Tab : ViewModelBase
{
    private string _IconPath,
        _LanguageResourceName;
    private ViewModelBase _ViewModel;

    /// <summary>
    /// The path to the icon to show on the tab.
    /// </summary>
    public string IconPath
    {
        get { return _IconPath; }
        set { SetProperty(ref _IconPath, value); }
    }

    /// <summary>
    /// The name of the entry in the language resource file to display on the tab.
    /// </summary>
    public string LanguageResourceName
    {
        get { return _LanguageResourceName; }
        set { SetProperty(ref _LanguageResourceName, value); }
    }

    /// <summary>
    /// The contents of the tab.
    /// </summary>
    public ViewModelBase ViewModel
    {
        get { return _ViewModel; }
        set { SetProperty(ref _ViewModel, value); }
    }
}

So what is the correct way to resolve this issue?

Answer 1

Converter is the best way to do it. Check out my answer here for a quick explanation. I've copied the Converter I define there below.

ResourceController is a simple Controller which gets a reference to a ResourceLoader and retrieves values via a method GetString(string resourceId).

public class ResourceTranslationConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        var valString = value as string;

        // If what is being converted is a string, return the resource translation
        // Else return something else, such as the object itself
        return valString == null ? value : ResourceController.GetString(valString);
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
        throw new NotImplementedException();
    }
}

Binding then works like:

<TextBlock Text="{Binding LanguageResourceName, Converter={StaticResource ResourceTranslationConverter}}" />

Make sure you've defined an accessible ResourceTranslationConverter. Possibly in the Page.Resources or even in your App.xaml (since you should only need one static reference).

Hope this helps and happy coding!