WPF Runtime Locale Change, reevaluate ValueConverters UI

Question

In a large WPF application, we have the possibility to change the language at runtime. We use WPF Localize Extension and resx-files for localization and it works great, exce

Answer 1

This is our solution. I hope I understood your problem that you want to change for example DateTime?

The Converter is a simple IValueConverter which convert the value to the current Language. Translator is a static class which holds (for example) the CurrentLanguage (en-en / de-de) as string.

The Behavior is needed to update the Bindings if the language has changed. We only need this implementation 3-4 times in the hole program, because it is only for the DateTime formating. All other texts are hold in a dynamic Resource..

But I think for your needs the Behavior is the right one.

Converter

public class CultureConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value != null)
        {
            DateTime dateTime;
            if(DateTime.TryParse(value.ToString(), out dateTime))
            {
                if(parameter != null)
                {
                    return dateTime.ToString(parameter.ToString(), new CultureInfo(Translator.CurrentLanguage));
                }
                return dateTime.ToString(new CultureInfo(Translator.CurrentLanguage));
            }
            return null;
        }
        return null;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return null;
    }
}

Behavior

public class CultureConverter : Behavior
{
    private FrameworkElement _HostingControl;
    private DependencyProperty _HostingControlDependencyProperty;

    protected override void OnAttached()
    {
        base.OnAttached();

        _HostingControl = AssociatedObject;

        _InitHostingControl();
        Translator.LanguageChanged += Translator_LanguageChanged;
    }

    protected override void OnDetaching()
    {
        Translator.LanguageChanged -= Translator_LanguageChanged;

        base.OnDetaching();
    }

    private void Translator_LanguageChanged(string languageCode)
    {
        if(_HostingControlDependencyProperty != null)
            _HostingControl.GetBindingExpression(_HostingControlDependencyProperty).UpdateTarget();
    }

    private void _InitHostingControl()
    {
        if(_HostingControl is TextBlock)
        {
            _HostingControlDependencyProperty = TextBlock.TextProperty;
        }
        else if (typeof(TextBox) == _HostingControl.GetType())
            _HostingControlDependencyProperty = TextBox.TextProperty;
    }

XAML

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