NavigationViewTemplateSettings is missing OpenPaneWidth

[michael-hawker]

Describe the bug

The NavigationView style references this binding:

microsoft-ui-xaml/dev/NavigationView/NavigationView.xaml

Line 472 in e4c5d34

OpenPaneLength="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.OpenPaneWidth}"

However this property does not exist on the NavgationViewTemplateSettings class: https://docs.microsoft.com/en-us/windows/winui/api/microsoft.ui.xaml.controls.navigationviewtemplatesettings

(I'm not sure how these are generated in the code base the h/cpp files with those names are empty.)

In either case, there is some mismatch between the style and the properties which should be resolved as this will cause binding reflection errors at runtime.

This is also another reason why improving x:Bind behaviors like #2508 #2237 would be valuable.

Steps to reproduce the bug

Copy NavigationView template into an app project, get warning about property on NavigationViewTemplateSettings not existing

Expected behavior

No errors in template

Screenshots

NuGet package version

Microsoft.UI.Xaml 2.7.0

Windows app type

• UWP
• Win32

Device form factor

No response

Windows version

No response

Additional context

No response

[michael-hawker]

Also occurs again here:

microsoft-ui-xaml/dev/NavigationView/NavigationView.xaml

Line 686 in e4c5d34

Width="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.OpenPaneWidth}"

[marcelwgn]

The code for that property is auto generated based on the IDL file. You can find the definition of the properties for the template settings here: https://github.com/microsoft/microsoft-ui-xaml/blob/main/dev/NavigationView/NavigationView.idl#L127

The behavior you are describing is partially a bug indeed. The property is not included in non-prerelease versions of WinUI 2 and as such, the property is not available in WinUI 2.7. If you are using a pre-release, the property will be available.

@MikeHillberg Do you think the property can be made public now given how long it has been part of the pre-releases (first added in #5800, March 2021)?

[StephenLPeters]

@ranjeshj I think we need to make this property public. this is pretty broken.

[StephenLPeters]

@karenbtlai FYI

[kmahone]

@karenbtlai please take a look.