title: Use "real" CultureInfo.CurrentCulture in WPF Binding, not CultureInfo from IetfLanguageTag
body: <p>In my case:</p>
  
  <p>I have a TextBlock Binding to a property of type DateTime.
  I want it to be displayed as the Regional settings of the User says.</p>
  
  <pre><code>&lt;TextBlock Text="{Binding Date, StringFormat={}{0:d}}" /&gt;
  </code></pre>
  
  <p>I am setting Language property as <a href="https://stackoverflow.com/questions/991526/wpf-xaml-bindings-and-currentculture-display">WPF XAML Bindings and CurrentCulture Display</a>
  says:</p>
  
  <pre><code>this.Language = XmlLanguage.GetLanguage(CultureInfo.CurrentCulture.IetfLanguageTag);
  </code></pre>
  
  <p>But with this line of code it just displays the text as the default format of CultureInfo
  with IetfLanguageTag of CurrentCulture says, not as the effective value selected in systems region settings says:</p>
  
  <p>(e.g. for "de-DE" <strong>dd.MM.yyyy</strong> is used instead of selected <strong>yyyy-MM-dd</strong>)</p>
  
  <p><img src="https://i.stack.imgur.com/bosWa.png" alt="Region settings: not the default but yyy-MM-dd is used"></p>
  
  <p>Is there a way Binding uses the correct format without defining ConverterCulture on every single Binding?</p>
  
  <p>In code</p>
  
  <pre><code>string.Format("{0:d}",Date);
  </code></pre>
  
  <p>uses the right Culture settings.</p>
  
  <p><strong>edit:</strong></p>
  
  <p>another way which doesn't work as desired (like this.Language = ... does):</p>
  
  <pre><code>xmlns:glob="clr-namespace:System.Globalization;assembly=mscorlib"
  </code></pre>
  
  <p>and</p>
  
  <pre><code>&lt;Binding Source="{x:Static glob:CultureInfo.CurrentCulture}" 
   Path="IetfLanguageTag" 
   ConverterCulture="{x:Static glob:CultureInfo.InvariantCulture}" /&gt;
  </code></pre>