title: Cannot bind to public property inside ResourceDirectory WinUI3/UWP
body: <p>So I am currently trying to bind a public static SolidColorBrush to a &quot;Filled&quot; property on a Rectangle inside a ResourceDirectory Style (inisde App.xaml).
  But I always get the Exception</p>
  <blockquote>
  <p>&quot;Type 'x' used after '{' must be a Markup Extention. Error code 0x09c6.&quot;</p>
  </blockquote>
  <p>My xaml code looks like this (inside App.xaml):</p>
  <pre><code>&lt;Rectangle
      x:Name=&quot;SelectionIndicator&quot;
      Width=&quot;4&quot;
      Height=&quot;24&quot;
      Fill=&quot;{x:Bind SomeNamespace:SomeClass.SomeColor}&quot;/&gt;
  </code></pre>
  <p>and my codebehind looks like this (inside public class called &quot;SomeClass&quot; in Namespace called &quot;SomeNamespace&quot;):</p>
  <pre><code>public static SolidColorBrush SomeColor = new(Colors.Red);
  </code></pre>
  <p>I know its possible to bind to a public static property with x:Bind in WinUI/UWP but this somehow doesnt work.
  I really need to bind from some code behind so I can implement INotifyPropertyChanged so I cant just create a new color resource.
  What is the correct way to implement my wanted behavior?
  Thanks in advance!</p>