From 930e2b062eba7dcf38fc4aed603376ff06f15f44 Mon Sep 17 00:00:00 2001
From: Brian Lagunas <brianlagunas@users.noreply.github.com>
Date: Fri, 16 Nov 2018 19:27:46 -0700
Subject: [PATCH] fixed #1625

I totally forgot to do a PR, so it's going directly into master because I do not want to redo all that work.
---
 .../ViewModels/MyMasterDetailViewModel.cs     |  8 +++--
 .../HelloWorld/Views/MyMasterDetail.xaml      |  6 ++--
 .../ModuleA/Views/MyTabbedPage.xaml           |  8 ++---
 .../Navigation/PageNavigationService.cs       | 29 ++++++++++++-------
 4 files changed, 32 insertions(+), 19 deletions(-)

diff --git a/Sandbox/Xamarin/HelloWorld/HelloWorld/HelloWorld/ViewModels/MyMasterDetailViewModel.cs b/Sandbox/Xamarin/HelloWorld/HelloWorld/HelloWorld/ViewModels/MyMasterDetailViewModel.cs
index b906070c0..0affcebbe 100644
--- a/Sandbox/Xamarin/HelloWorld/HelloWorld/HelloWorld/ViewModels/MyMasterDetailViewModel.cs
+++ b/Sandbox/Xamarin/HelloWorld/HelloWorld/HelloWorld/ViewModels/MyMasterDetailViewModel.cs
@@ -20,9 +20,13 @@ public MyMasterDetailViewModel(INavigationService navigationService)
             NavigateCommand = new DelegateCommand<string>(Navigate);
         }
 
-        private void Navigate(string name)
+        private async void Navigate(string name)
         {
-            _navigationService.NavigateAsync(name);
+            var result = await _navigationService.NavigateAsync(name);
+            if (!result.Success)
+            {
+
+            }
         }
 
         public override void OnNavigatedFrom(INavigationParameters parameters)
diff --git a/Sandbox/Xamarin/HelloWorld/HelloWorld/HelloWorld/Views/MyMasterDetail.xaml b/Sandbox/Xamarin/HelloWorld/HelloWorld/HelloWorld/Views/MyMasterDetail.xaml
index 06aa39a52..477604499 100644
--- a/Sandbox/Xamarin/HelloWorld/HelloWorld/HelloWorld/Views/MyMasterDetail.xaml
+++ b/Sandbox/Xamarin/HelloWorld/HelloWorld/HelloWorld/Views/MyMasterDetail.xaml
@@ -10,9 +10,9 @@
         <ContentPage Title="Default">
             <StackLayout>
                 <Button Text="MainPage" Command="{Binding NavigateCommand}" CommandParameter="MyNavigationPage/MainPage" />
-                <Button Text="ViewA" Command="{Binding NavigateCommand}" CommandParameter="MyNavigationPage/ViewA" />
-                <Button Text="ViewB" Command="{Binding NavigateCommand}" CommandParameter="MyNavigationPage/ViewB" />
-                <Button Text="ViewC" Command="{Binding NavigateCommand}" CommandParameter="MyNavigationPage/ViewC" />
+                <Button Text="ViewA" Command="{Binding NavigateCommand}" CommandParameter="MyTabbedPage?selectedTab=ViewA" />
+                <Button Text="ViewB" Command="{Binding NavigateCommand}" CommandParameter="MyTabbedPage?selectedTab=ViewB" />
+                <Button Text="ViewC" Command="{Binding NavigateCommand}" CommandParameter="MyTabbedPage?selectedTab=ViewC" />
                 <Button Text="XamlNav" Command="{nav:NavigateTo 'MyNavigationPage/ViewA'}" />
             </StackLayout>
         </ContentPage>
diff --git a/Sandbox/Xamarin/HelloWorld/ModuleA/Views/MyTabbedPage.xaml b/Sandbox/Xamarin/HelloWorld/ModuleA/Views/MyTabbedPage.xaml
index 575e98aff..80a6e158e 100644
--- a/Sandbox/Xamarin/HelloWorld/ModuleA/Views/MyTabbedPage.xaml
+++ b/Sandbox/Xamarin/HelloWorld/ModuleA/Views/MyTabbedPage.xaml
@@ -18,16 +18,16 @@
 		</x:Arguments>
 	</NavigationPage>
 
-    <!--<NavigationPage Title="View B">
+    <NavigationPage Title="View B">
         <x:Arguments>
 			<local:ViewB Title="View B" />
 		</x:Arguments>
 	</NavigationPage>
 
-	<local:ViewC Title="View C" />-->
+	<local:ViewC Title="View C" />
 
     <!--<local:ViewA Title="View A" />-->
-    <local:ViewB Title="View B"/>
-    <local:ViewC Title="View C"/>
+    <!--<local:ViewB Title="View B"/>-->
+    <!--<local:ViewC Title="View C"/>-->
 
 </TabbedPage>
\ No newline at end of file
diff --git a/Source/Xamarin/Prism.Forms/Navigation/PageNavigationService.cs b/Source/Xamarin/Prism.Forms/Navigation/PageNavigationService.cs
index 5d3796362..c6d939380 100644
--- a/Source/Xamarin/Prism.Forms/Navigation/PageNavigationService.cs
+++ b/Source/Xamarin/Prism.Forms/Navigation/PageNavigationService.cs
@@ -575,19 +575,22 @@ protected virtual async Task ProcessNavigationForMasterDetailPage(MasterDetailPa
             {
                 detailIsNavPage = true;
 
-                //first we check to see if we are being forced to reuse the NavPage by checking the interface
-                reuseNavPage = !GetClearNavigationPageNavigationStack(navPage);
-
-                if (!reuseNavPage)
+                //we only care if we the next segment is also a NavigationPage.
+                if (PageUtilities.IsSameOrSubclassOf<NavigationPage>(nextSegmentType))
                 {
-                    //if we weren't forced to reuse the NavPage, then let's check the NavPage.CurrentPage against the next segment type as we don't want to recreate the entire nav stack
-                    //just in case the user is trying to navigate to the same page which may be nested in a NavPage
-                    var nextPageType = PageNavigationRegistry.GetPageType(UriParsingHelper.GetSegmentName(segments.Peek()));
-                    var currentPageType = navPage.CurrentPage.GetType();
+                    //first we check to see if we are being forced to reuse the NavPage by checking the interface
+                    reuseNavPage = !GetClearNavigationPageNavigationStack(navPage);
 
-                    if (nextPageType == currentPageType)
+                    if (!reuseNavPage)
                     {
-                        reuseNavPage = true;
+                        //if we weren't forced to reuse the NavPage, then let's check the NavPage.CurrentPage against the next segment type as we don't want to recreate the entire nav stack
+                        //just in case the user is trying to navigate to the same page which may be nested in a NavPage
+                        var nextPageType = PageNavigationRegistry.GetPageType(UriParsingHelper.GetSegmentName(segments.Peek()));
+                        var currentPageType = navPage.CurrentPage.GetType();
+                        if (nextPageType == currentPageType)
+                        {
+                            reuseNavPage = true;
+                        }
                     }
                 }
             }
@@ -597,6 +600,12 @@ protected virtual async Task ProcessNavigationForMasterDetailPage(MasterDetailPa
                 await ProcessNavigation(detail, segments, parameters, useModalNavigation, animated);
                 await DoNavigateAction(null, nextSegment, detail, parameters, onNavigationActionCompleted: () =>
                  {
+                     if (detail is TabbedPage && nextSegment.Contains(KnownNavigationParameters.SelectedTab))
+                     {
+                         var segmentParams = UriParsingHelper.GetSegmentParameters(nextSegment);
+                         SelectPageTab(detail, segmentParams);
+                     }
+
                      currentPage.IsPresented = isPresented;
                  });
                 return;