title: Change theme at runtime
body: <p>I have a WPF application with a theme (ShinyRed.xaml) and I want to have a button that when clicked changes the theme to ShinyBlue.xaml</p>
  
  <p>I load in the theme initially in App.xaml:</p>
  
  <pre><code>&lt;Application.Resources&gt;
      &lt;ResourceDictionary Source="/Themes/ShinyBlue.xaml"/&gt;
  &lt;/Application.Resources&gt;
  </code></pre>
  
  <p>How might I do this?</p>