title: Change custom color for Rectangle.Fill or Grid.Background
body: <p>i can change custom color Rectangle with something like : "#A125AA" in xaml.</p>
  
  <p>But i don't know where to find code change custom color i have</p>
  
  <p>i just know code for color arealy have</p>
  
  <pre><code>this.gridgcolor.Background = new SolidColorBrush(Colors.Blue);
  </code></pre>