Issue with NavigationViewExtensions.SelectedIndex Property

[michael-hawker]

I'm submitting a...

• Bug report (I searched for similar issues and did not find one)

Current behavior

In some advanced scenarios, the selected item of the NavigationView is set to null when the user selects an item.

Expected behavior

SelectedItem not set to null...

Minimal reproduction of the problem with instructions

Wasn't able to see it in sample app even though my project uses the same structure. Think it has to do with something binding to the selecteditem elsewhere maybe. Anyway, was able to fix the issue with logic here on line 148.

Should be

            if (value >= 0 && value < navview.MenuItems.Count)
            {
                // Only update if we need to.
                if (navview.SelectedItem == null || !navview.SelectedItem.Equals(navview.MenuItems[value] as NavigationViewItem))
                {
                    navview.SelectedItem = navview.MenuItems[value];
                }
            }

Then worked like a charm, thought there was something wrong with my app... I'll submit a PR soon.

Environment

Nuget Package(s): 2.2

Package Version(s): 

Windows 10 Build Number:
- [ ] Anniversary Update (14393) 
- [ ] Creators Update (15063)
- [x] Fall Creators Update (16299)
- [ ] Insider Build (build number: )

App min and target version:
- [ ] Anniversary Update (14393) 
- [ ] Creators Update (15063)
- [x] Fall Creators Update (16299)
- [ ] Insider Build (xxxxx)

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

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