title: WPF control styles - how to override a single setter value in a global control style ResourceDictionary file in a separate ResourceDictionary file
body: <p>I declare the following ResourceDictionary, TargetType=&quot;TextBlock&quot; in the App.xaml file:</p>
  <pre><code>    &lt;ResourceDictionary&gt;
          &lt;Style TargetType=&quot;TextBlock&quot;&gt;
              &lt;Setter Property=&quot;Foreground&quot; Value=&quot;Red&quot;/&gt;
              &lt;Setter Property=&quot;FontStyle&quot; Value=&quot;Italic&quot;/&gt;
              &lt;Setter Property=&quot;FontSize&quot; Value=&quot;20&quot;/&gt;
          &lt;/Style&gt;
      &lt;/ResourceDictionary&gt;
  </code></pre>
  <p>Later, after the application has started, I want to be able to on-demand load another resource file (MyCustomResources.xaml) that has a style declaration, again with TargetType=&quot;TextBlock&quot;, but with ONLY one Setter that declares a Forground color of &quot;Green&quot;.
  The &quot;Green&quot; Foreground color will need to globally override the original Foreground &quot;Red&quot;.</p>
  <pre><code>&lt;ResourceDictionary&gt;
      &lt;Style TargetType=&quot;TextBlock&quot;&gt;
          &lt;Setter Property=&quot;Foreground&quot; Value=&quot;Green&quot;/&gt;
      &lt;/Style&gt;
  &lt;/ResourceDictionary&gt;
  </code></pre>
  <p>For this application, overriding the Foreground color for a TextBlock in a local view xaml file is not acceptable.</p>
  <p>I want to still keep and use the other two global Setter properties for FontStyle and FontSize for TextBlock controls declared in the App.xaml file, without having to declare them again in the MyCustomResources.xaml file.</p>
  <p>Is it possible to do what I am describing here, or some other way?</p>