CurrentUICulture 忽略区域和语言设置

Question

Windows 7 区域和语言对话框中的各种设置为 CurrentCulture 对象的属性提供值。但是，WPF 控件似乎改用 CurrentUICulture，导致完全无法尊重用户的偏好。

例如，在我的工作站上，WPF 控件似乎使用的是 en-US 的 CurrentUICulture，导致它们以美国格式 M/d/yyyy 显示日期，而不是在区域和语言对话框中指定的澳大利亚格式。

在数据绑定中明确指定 en-AU 文化会导致相关控件使用默认的澳大利亚格式，但它会继续忽略用户指定的格式。这很奇怪；进入应用程序我验证了 DateTimeFormatInfo.CurrentInfo == Thread.CurrentThread.CurrentCulture.DateTimeFormat （相同的对象）和 DateTimeFormatInfo.CurrentInfo.ShortDatePattern == "yyyy-MM-dd" （我设置的一个值，以便我可以确定用户偏好或正在选择默认值）。一切都如预期的那样，所以从表面上看，最大的问题是如何说服 WPF 控件和数据绑定使用 CurrentCulture 而不是 CurrentUICulture。

我们应该如何让 WPF 应用程序尊重区域和语言设置？

---

基于 Sphinxx 的回答，我重写了 Binding 类的 both 构造函数，以提供与标准标记的更完整兼容性。

using System.Globalization;
using System.Windows.Data;

namespace ScriptedRoutePlayback
{
  public class Bind : Binding
  {
    public Bind()
    {
      ConverterCulture = CultureInfo.CurrentCulture;
    }
    public Bind(string path) : base(path)
    {
      ConverterCulture = CultureInfo.CurrentCulture;
    }
  }
}

---

进一步的实验表明，您可以使用 x:Static 在标记中引用 System.Globalization.CultureInfo.CurrentCulture。这在运行时是完全成功的，但在设计时是灾难，因为绑定编辑器不断删除它。更好的解决方案是一个帮助类来遍历窗口的 DOM 并修复它找到的每个 Binding 的 ConverterCulture。

using System;
using System.Windows;
using System.Windows.Data;
using System.ComponentModel;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;

namespace ScriptedRoutePlayback
{
  public static class DependencyHelper
  {
    static Attribute[] __attrsForDP = new Attribute[] { new PropertyFilterAttribute(PropertyFilterOptions.SetValues | PropertyFilterOptions.UnsetValues | PropertyFilterOptions.Valid) };

    public static IList<DependencyProperty> GetProperties(Object element, bool isAttached = false)
    {
      if (element == null) throw new ArgumentNullException("element");

      List<DependencyProperty> properties = new List<DependencyProperty>();

      foreach (PropertyDescriptor pd in TypeDescriptor.GetProperties(element, __attrsForDP))
      {
        DependencyPropertyDescriptor dpd = DependencyPropertyDescriptor.FromProperty(pd);
        if (dpd != null && dpd.IsAttached == isAttached)
        {
          properties.Add(dpd.DependencyProperty);
        }
      }

      return properties;
    }

    public static IEnumerable<Binding> EnumerateBindings(DependencyObject dependencyObject)
    {
      if (dependencyObject == null) throw new ArgumentNullException("dependencyObject");

      LocalValueEnumerator lve = dependencyObject.GetLocalValueEnumerator();

      while (lve.MoveNext())
      {
        LocalValueEntry entry = lve.Current;

        if (BindingOperations.IsDataBound(dependencyObject, entry.Property))
        {
          Binding binding = (entry.Value as BindingExpression).ParentBinding;
          yield return binding;
        }
      }
    }

    /// <summary>
    /// Use in the constructor of each Window, after initialisation.
    /// Pass "this" as the dependency object and omit other parameters to have 
    /// all the bindings in the window updated to respect user customisations 
    /// of regional settings. If you want a specific culture then you can pass 
    /// values to recurse and cultureInfo. Setting recurse to false allows you 
    /// to update the bindings on a single dependency object.
    /// </summary>
    /// <param name="dependencyObject">Root dependency object for binding change treewalk</param>
    /// <param name="recurse">A value of true causes processing of child dependency objects</param>
    /// <param name="cultureInfo">Defaults to user customisations of regional settings</param>
    public static void FixBindingCultures(DependencyObject dependencyObject, bool recurse = true, CultureInfo cultureInfo = null)
    {
      if (dependencyObject == null) throw new ArgumentNullException("dependencyObject");
      try
      {
        foreach (object child in LogicalTreeHelper.GetChildren(dependencyObject))
        {
          if (child is DependencyObject)
          {
            //may have bound properties
            DependencyObject childDependencyObject = child as DependencyObject;
            var dProps = DependencyHelper.GetProperties(childDependencyObject);
            foreach (DependencyProperty dependencyProperty in dProps)
              RegenerateBinding(childDependencyObject, dependencyProperty, cultureInfo);
            //may have children
            if (recurse)
              FixBindingCultures(childDependencyObject, recurse, cultureInfo);
          }
        }
      }
      catch (Exception ex)
      {
        Trace.TraceError(ex.Message);
      }
    }

    public static void RegenerateBinding(DependencyObject dependencyObject, DependencyProperty dependencyProperty, CultureInfo cultureInfo = null)
    {
      Binding oldBinding = BindingOperations.GetBinding(dependencyObject, dependencyProperty);
      if (oldBinding != null)
        try
        {
          //Bindings cannot be changed after they are used.
          //But they can be regenerated with changes.
          Binding newBinding = new Binding()
          {
            Converter = oldBinding.Converter,
            ConverterCulture = cultureInfo ?? CultureInfo.CurrentCulture,
            ConverterParameter = oldBinding.ConverterParameter,
            FallbackValue = oldBinding.FallbackValue,
            IsAsync = oldBinding.IsAsync,
            Mode = oldBinding.Mode,
            NotifyOnSourceUpdated = oldBinding.NotifyOnSourceUpdated,
            NotifyOnTargetUpdated = oldBinding.NotifyOnValidationError,
            Path = oldBinding.Path,
            StringFormat = oldBinding.StringFormat,
            TargetNullValue = oldBinding.TargetNullValue,
            UpdateSourceExceptionFilter = oldBinding.UpdateSourceExceptionFilter,
            UpdateSourceTrigger = oldBinding.UpdateSourceTrigger,
            ValidatesOnDataErrors = oldBinding.ValidatesOnDataErrors,
            ValidatesOnExceptions = oldBinding.ValidatesOnExceptions,
            XPath = oldBinding.XPath
          };
          //set only one of ElementName, RelativeSource, Source
          if (oldBinding.ElementName != null)
            newBinding.ElementName = oldBinding.ElementName;
          else if (oldBinding.RelativeSource != null)
            newBinding.Source = oldBinding.Source;
          else
            newBinding.RelativeSource = oldBinding.RelativeSource;
          BindingOperations.ClearBinding(dependencyObject, dependencyProperty);
          BindingOperations.SetBinding(dependencyObject, dependencyProperty, newBinding);
        }
        catch (Exception ex)
        {
          Trace.TraceError(ex.Message);
        }
    }

  }
}

Answer 1

This SO post (WPF/Silverlight) 有一个指向 this article（仅限 WPF）的链接，说明如何使用 CurrentCulture 作为您的应用程序的默认设置。这能解决你的问题吗？

编辑：

使用“区域和语言”中的自定义设置而不是当前语言的默认设置进行绑定需要更多技巧。 This post 得出结论，每个绑定的ConverterCulture 也必须显式设置为CultureInfo.CurrentCulture。以下是一些 DateTime 测试：

<!-- Culture-aware(?) bindings -->
<StackPanel DataContext="{Binding Source={x:Static sys:DateTime.Now}}" >

    <!-- WPF's default en-US formatting (regardless of any culture/language settings) -->
    <TextBlock Text="{Binding Path=.}" />

    <!-- *Default* norwegian settings (dd.MM.YYY) -->
    <TextBlock Text="{Binding Path=., ConverterCulture=nb-NO}" />

    <!-- Norwegian settings from the "Region and Languague" dialog (d.M.YY) -->
    <TextBlock Text="{Binding Path=., ConverterCulture={x:Static sysglb:CultureInfo.CurrentCulture}}" />

    <!-- Hiding ConverterCulture initialization in our own custom Binding class as suggested here:
         https://stackoverflow.com/questions/5831455/use-real-cultureinfo-currentculture-in-wpf-binding-not-cultureinfo-from-ietfl#5937477 -->
    <TextBlock Text="{local:CultureAwareBinding Path=.}" />

</StackPanel>

自定义绑定类：

public class CultureAwareBinding : Binding
{
    public CultureAwareBinding()
    {
        this.ConverterCulture = System.Globalization.CultureInfo.CurrentCulture;
    }
}

这一切最终在挪威机器上看起来像这样：

Answer 2

在 WPF 中有一种非常肮脏的方法，但据我所知，它是最好的，因为它无需任何其他额外代码或具有特定的文化感知绑定即可工作。您唯一需要做的就是在应用程序启动时调用 SetFrameworkElementLanguageDirty 方法（在答案下方），甚至在应用程序的构造函数中调用更好。

方法 cmets 是不言自明的，但简而言之，该方法使用 CurrentCulture 覆盖 FrameworkElement 的 LanguageProperty 的默认元数据，包括用户从窗口进行的特定修改（如果有）。缩小/肮脏的部分是它使用反射来设置 XmlLanguage 对象的私有字段。

    /// <summary>
    ///   Sets the default language for all FrameworkElements in the application to the user's system's culture (rather than
    ///   the default "en-US").
    ///   The WPF binding will use that default language when converting types to their string representations (DateTime,
    ///   decimal...).
    /// </summary>        
    public static void SetFrameworkElementLanguageDirty()
    {
        // Note that the language you get from "XmlLanguage.GetLanguage(currentCulture.IetfLanguageTag)"
        // doesn't include specific user customizations, for example of date and time formats (Windows date and time settings).            
        var xmlLanguage = XmlLanguage.GetLanguage(Thread.CurrentThread.CurrentCulture.IetfLanguageTag);
        SetPrivateField(xmlLanguage, "_equivalentCulture", Thread.CurrentThread.CurrentCulture);

        FrameworkElement.LanguageProperty.OverrideMetadata(typeof(FrameworkElement), new FrameworkPropertyMetadata(xmlLanguage));
    }

SetPrivateField 方法可能如下所示。

    private static void SetPrivateField(object obj, string name, object value)
    {
        var privateField = obj.GetType().GetField(name, BindingFlags.Instance | BindingFlags.NonPublic);
        if (privateField == null) throw new ArgumentException($"{obj.GetType()} doesn't have a private field called '{name}'.");

        privateField.SetValue(obj, value);
    }