TrTextIdConverter.cs

using Avalonia.Data.Converters;
using System;
using System.Globalization;

namespace CodingSeb.Localization.Avalonia
{
    /// <summary>
    /// Converter to Translate a the binding textId (In CurrentLanguage or if specified in LanguageId)
    /// If Translation don't exist return DefaultText
    /// Not usable in TwoWay Binding mode.
    /// </summary>
    public class TrTextIdConverter : IValueConverter
    {
        public TrTextIdConverter()
        {
            //WeakEventManager<Loc, CurrentLanguageChangedEventArgs>.AddHandler(Loc.Instance, nameof(Loc.Instance.CurrentLanguageChanged), CurrentLanguageChanged);
        }

        ~TrTextIdConverter()
        {
            //WeakEventManager<Loc, CurrentLanguageChangedEventArgs>.RemoveHandler(Loc.Instance, nameof(Loc.Instance.CurrentLanguageChanged), CurrentLanguageChanged);
        }

        /// <summary>
        /// The text to return if no text correspond to textId in the current language
        /// </summary>
        public string DefaultText { get; set; }

        /// <summary>
        /// The language id in which to get the translation. To Specify if not CurrentLanguage
        /// </summary>
        public string LanguageId { get; set; }

        /// <summary>
        /// A string format where will be injected the binding
        /// by Default => {0}
        /// </summary>
        public string TextIdStringFormat { get; set; } = "{0}";

        /// <summary>
        /// AllowTo use a converter on the binded value before to inject it in the TextId
        /// </summary>
        public IValueConverter PreConverter { get; set; }

        /// <summary>
        /// To provide a prefix to add at the begining of the translated text.
        /// </summary>
        public string Prefix { get; set; } = string.Empty;

        /// <summary>
        /// To provide a suffix to add at the end of the translated text.
        /// </summary>
        public string Suffix { get; set; } = string.Empty;

        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            string textId = PreConverter?.Convert(value, null, null, null)?.ToString() ?? value?.ToString();
            return Prefix + (string.IsNullOrEmpty(textId) ? "" : Loc.Tr(string.Format(TextIdStringFormat, textId), DefaultText?.Replace("[apos]", "'"), LanguageId)) + Suffix;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) => throw new NotImplementedException();

        public object ProvideValue(IServiceProvider serviceProvider)
        {
            //SetXamlObjects(serviceProvider);

            return this;
        }

        private void CurrentLanguageChanged(object sender, CurrentLanguageChangedEventArgs e)
        {
            //if (xamlTargetObject != null && xamlDependencyProperty != null)
            //{
            //    if(IsInAMultiBinding)
            //        BindingOperations.GetMultiBindingExpression(xamlTargetObject, xamlDependencyProperty)?.UpdateTarget();
            //    else
            //        BindingOperations.GetBindingExpression(xamlTargetObject, xamlDependencyProperty)?.UpdateTarget();
            //}
        }
    }
}