Prism Tabbed Navigation

INavigationServiceExtensions.cs

using System;
using System.Linq;
using System.Threading.Tasks;
using Prism.Common;
using Xamarin.Forms;

namespace Prism.Navigation
{
    public static class INavigationServiceExtensions
    {
        public static async Task<INavigationResult> NavigateToTab(this INavigationService navigationService, string tabName, INavigationParameters parameters)
        {
            if (parameters == null)
                parameters = new NavigationParameters();

            var result = new NavigationResult { Success = true };

            try
            {
                var page = (navigationService as IPageAware).Page;

                TabbedPage tabbedPage = null;

                switch(page.Parent)
                {
                    case TabbedPage tabbed:
                        tabbedPage = tabbed;
                        break;
                    case NavigationPage navigationPage;
                        if (navigationPage.Parent is TabbedPage parent)
                            tabbedPage = parent;
                        break;
                }

                if (tabbedPage == null)
                    throw new NullReferenceException("The current page does not appear to have a TabbedPage parent");

                if(PageUtilities.CanNavigate(page, parameters) && await PageUtilities.CanNavigateAsync(page, parameters))
                {
                    tabbedPage.CurrentPage = tabbedPage.Children.First(c => c.GetType() == PageNavigationRegistry.GetPageType(tabName));
                    
                    PageUtilities.OnNavigatedFrom(page, parameters);
                    PageUtilities.OnNavigatedTo(tabbedPage.CurrentPage, parameters);
                }

            }
            catch (Exception ex)
            {
                result.Success = false;
                result.Exception = ex;
            }

            return result;
        }
    }
}