Question

在大型WPF应用程序中，我们可以在运行时更改语言。我们使用WPF Localize Extension和resx文件进行本地化，除了UI中使用的转换器外，它工作得很好。如果在绑定中，ValueConverter是特定于文化的，则不会在语言更改时更新生成的文本。

如何让WPF在应用程序范围内更新所有已转换的绑定？

编辑：目前我们已经通过制作ValueConverters MultiValueConverters并将区域设置添加为额外值进行了实验。这样，值源值会更改，并且结果会更新。但这很麻烦，很难看。

<MultiBinding Converter="{StaticResource _codeMultiConverter}" ConverterParameter="ZSLOOPAKT">
  <Binding Path="ActivityCode" />
  <Binding Source="{x:Static lex:LocalizeDictionary.Instance}" Path="Culture" />
  <Binding Source="{x:Static RIEnums:CodeTypeInfo+CodeDisplayMode.Both}" />
</MultiBinding>

相关： Run-time culture change and IValueConverter in a binding （我没有选择手动为每个字段提高propertychanged）

Answer 1

作为一个选项 - 您可以围绕Binding创建包装器标记扩展，如下所示：

public class LocBindingExtension : MarkupExtension {
    public BindingBase Binding { get; set; }

    public override object ProvideValue(IServiceProvider serviceProvider) {
        if (Binding == null)
            return null;

        // Binding is by itself MarkupExtension
        // Call its ProvideValue
        var expression = Binding.ProvideValue(serviceProvider) as BindingExpressionBase;
        if (expression != null) {                
            // if got expression - create weak reference
            // you don't want for this to leak memory by preventing binding from GC
            var wr = new WeakReference<BindingExpressionBase>(expression);
            PropertyChangedEventHandler handler = null;
            handler = (o, e) => {                    
                if (e.PropertyName == nameof(LocalizeDictionary.Instance.Culture)) {
                    BindingExpressionBase target;
                    // when culture changed and our binding expression is still alive - update target
                    if (wr.TryGetTarget(out target))
                        target.UpdateTarget();
                    else
                        // if dead - unsubsribe
                        LocalizeDictionary.Instance.PropertyChanged -= handler;
                }

            };
            LocalizeDictionary.Instance.PropertyChanged += handler;
            return expression;
        }
        // return self if there is no binding target (if we use extension inside a template for example)
        return this;  
    }
}

像这样使用：

<TextBlock Text="{my:LocBinding Binding={Binding ActivityCode, Converter={StaticResource myConverter}}}" />

您可以提供任何绑定（包括MultiBinding）并使用可以应用绑定的任何属性。

如果您认为即使这样过于冗长 - 您也可以通过镜像标记扩展所需的Binding类的所有属性并将它们转发到底层绑定来以不同的方式包装绑定。在这种情况下，您将需要编写更多代码，并且您需要为Binding和MultiBinding分别设置类（如果您还需要MultiBinding）。最好的方法是继承Binding并覆盖它ProvideValue，但它不是虚拟的，所以不可能这样做，我也找不到任何其他的您可以覆盖以实现结果的方法。这是一个只有2个绑定属性的草图：

public class LocBindingExtension : MarkupExtension {
    private readonly Binding _inner;
    public LocBindingExtension() {
        _inner = new Binding();
    }

    public LocBindingExtension(PropertyPath path) {
        _inner = new Binding();
        this.Path = path;
    }

    public IValueConverter Converter
    {
        get { return _inner.Converter; }
        set { _inner.Converter = value; }
    }

    public PropertyPath Path
    {
        get { return _inner.Path; }
        set { _inner.Path = value; }
    }

    public override object ProvideValue(IServiceProvider serviceProvider) {            
        // Binding is by itself MarkupExtension
        // Call its ProvideValue
        var expression = _inner.ProvideValue(serviceProvider) as BindingExpressionBase;
        if (expression != null) {                
            // if got expression - create weak reference
            // you don't want for this to leak memory by preventing binding from GC
            var wr = new WeakReference<BindingExpressionBase>(expression);
            PropertyChangedEventHandler handler = null;
            handler = (o, e) => {                    
                if (e.PropertyName == nameof(LocalizeDictionary.Instance.Culture)) {
                    BindingExpressionBase target;
                    // when culture changed and our binding expression is still alive - update target
                    if (wr.TryGetTarget(out target))
                        target.UpdateTarget();
                    else
                        // if dead - unsubsribe
                        LocalizeDictionary.Instance.PropertyChanged -= handler;
                }

            };
            LocalizeDictionary.Instance.PropertyChanged += handler;
            return expression;
        }
        // return self if there is no binding target (if we use extension inside a template for example)
        return this;  
    }
}

然后将使用简化为：

<TextBlock Text="{my:LocBinding ActivityCode, Converter={StaticResource myConverter}}" />

您可以根据需要添加更多属性（例如Mode等）。

Answer 2

这是我们的解决方案。我希望我理解您要更改的问题，例如DateTime？

Converter是一个简单的IValueConverter，它将值转换为当前语言。 Translator是一个静态类，其中包含（例如）CurrentLanguage（ en-en / de-de ）string

如果语言已更改，则需要Behavior来更新Bindings。我们在孔程序中只需要执行3-4次，因为它仅用于DateTime格式化。所有其他文本都保存在动态资源中..

但我认为根据您的需要，Behavior是正确的。

转换器

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;
    }
}

行为

public class CultureConverter : Behavior<FrameworkElement>
{
    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

<Window.Resources>
    <XamlConverter:CultureConverter x:Key="CultureConverter"/>
<Window.Resources>


<DataGridTemplateColumn.CellTemplate>
    <DataTemplate>
        <TextBlock 
            Text="{Binding CreatedOn, ConverterParameter=f, Converter={StaticResource CultureConverter}, UpdateSourceTrigger=PropertyChanged}">
            <i:Interaction.Behaviors>
                <Behaviors:CultureConverter/>
            </i:Interaction.Behaviors>
        </TextBlock>
    </DataTemplate>
</DataGridTemplateColumn.CellTemplate>

WPF运行时区域设置更改，重新评估ValueConverters UI

2 个答案:

转换器

行为

XAML

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