Changing navigation bar title when inside a tabbed page.

Hi, I am a xamarin.forms beginner, just wondering how can I change navigation bar's title when its in tabbed page? code as following :

public TabbedPageDemoPage() { Children.Add(new PageA() { Title = "PageA_tabbutton_text", Icon = "pageA_icon.png" }); Children.Add(new PageB() { Title = "PageB_tabbutton_text", Icon = "pageB_icon.png" }); Children.Add(new PageC() { Title = "PageC_tabbutton_text", Icon = "pageC_icon.png" }); Title = "Navigation Title"; // <---- I want change bar title when I tabbed pageA tab button so title become : "Page A Title" }

many thanks indeed.

regards,