title: How To Change Navigation Bar Color?
body: <p>Using Xamarin Forms Pcl &amp; Prism Library
  in side APP.CS</p>
  
  <pre><code>protected override void OnInitialized()
  {
     //Initialize();
  
     InitializeComponent();
  
     NavigationService.NavigateAsync("NavigationPage/MainPage");
  }
  
  protected override void RegisterTypes()
  {
      Container.RegisterTypeForNavigation&lt;NavigationPage&gt;();
      Container.RegisterTypeForNavigation&lt;MainPage,MainPageViewModel&gt;
      ("MainPage");
  }
  </code></pre>
  
  <p>inside MainPage.Xaml</p>
  
  <pre><code>Title="Main Page" 
  NavigationPage.HasNavigationBar="True"
  NavigationPage.BarTextColor="Black"
  NavigationPage.BarBackgroundColor="Red"
  </code></pre>
  
  <p>but it Never Changes the NavigationBar Color.</p>