The Back button does not work with MasterDetailView

[Kapranov98]

I'm submitting a...

Hello! I downloaded the Nightly version of Windows Template Studio and created a project with NavigationView and MasterDetailView (Code Behind). But after compiling I found that in compact mode, the NavView's Back button does not work with MasterDetailView, which makes it impossible to return from DetailPage to ListView.

The problem manifests itself only if the page with MasterDetailView is the main one and the transition to it is carried out immediately after the launch of the application.

Minimal reproduction of the problem with instructions

Project for example: App5.zip

Environment

Nuget Package(s): 
- [x] Microsoft.UI.Xaml (2.0.181018003)
- [x] Microsoft.Toolkit.Uwp.UI.Controls (5.0.0)

Package Version(s): 

Windows 10 Build Number:
- [x] October 2018 Update (17763)

App min and target version:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [x] October 2018 Update (17763)
- [x] Insider Build (xxxxx)

Device form factor:
- [x] Desktop
- [ ] Mobile
- [ ] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio 
- [x] 2017 (version: 15.8.9)
- [ ] 2017 Preview (version: )

[sibille]

@nmetulev or @skendrot, could you have a look? This seems to happen only if there's no back stack on the frame. Do we have to wire up things differently for the first navigation, or can you handle this on the control? Tracking issue on our side is: microsoft/TemplateStudio#2732

[skendrot]

Thanks for reporting @Kapranov98. Could you please provide minimal reproducible sample that does not include WTS?

[crutkas]

NavView + master detail where Master detail is first time.

[skendrot]

Sounds like there might be two issues

1. If there is no Frame being used with the new NavView. Not sure why anyone would do this...
2. If the MasterDetailsView is the first item in the Frame.

We'll have to reflect into the BackRequested event of the nav view. As previously noted we did not hook into this event because you cannot mark it as handled. However, we should hook into it and use it IFF a frame is not present OR the frame cannot navigate back and we are in a collapsed details state

[Kapranov98]

As an example, a project without WTS:
App2.zip

[sibille]

@skendrot, sounds good to me!

[crutkas]

Ping to stay open

[crutkas]

@michael-hawker, :)