StickyHeaderBehavior would not take effect in 7.0.0.preview5 if we switch NavigationView

[zhuxb711]

Describe the bug

StickyHeaderBehavior would not take effect in 7.0.0.preview5 if we use ListView.HeaderTemplate to define the layout and set custom object to ListView.Header

• Is this bug a regression in the toolkit? If so, what toolkit version did you last see it work:

Steps to Reproduce

• Can this be reproduced in the Sample App? (Either in a sample as-is or with new XAML pasted in the editor.) If so, please provide custom XAML or steps to reproduce. If not, let us know why it can't be reproduced (e.g. more complex setup, environment, dependencies, etc...)

Steps to reproduce the behavior:

1. Use HeaderTemplate, and set Header (some custion class object) in C#
2. Header will not be sticky and will move with ListViewItems

Expected behavior

Header should be sticky

Screenshots

If applicable, add screenshots to help explain your problem.

Environment

NuGet Package(s): 7.0.0 preview-5

Package Version(s): 

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] May 2019 Update (18362)
- [x] May 2020 Update (19041)
- [ ] Insider Build (build number: )

App min and target version:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [x] May 2019 Update (18362)
- [x] May 2020 Update (19041)
- [ ] Insider Build (xxxxx)

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

Visual Studio 
- [ ] 2017 (version: )
- [x] 2019 (version: latest) 
- [ ] 2019 Preview (version: )

Hello zhuxb711, thank you for opening an issue with us!

I have automatically added a "needs triage" label to help get things started. Our team will analyze and investigate the issue, and escalate it to the relevant team if possible. Other community members may also look into the issue and provide feedback 🙌

[michael-hawker]

@zhuxb711 all the ScrollHeader control did in 6.1 (and 7.0.0-preview4) was attach the behavior to the parent ListView, we didn't change any of its functionality. I don't think it ever supported using a HeaderTemplate with it as it was always looking for the Header content.

If this somehow worked for you, can you please share the XAML that will indicate this issue in the Sample App for us? You can just use a <x:String>Sample Text</x:String> to mimic some generic data being bound to the Header property.

Is there a reason you need a HeaderTemplate specifically and can't just bind your data object within the XAML within the Header itself?

[zhuxb711]

I changed my code and got a bug.
If I switch NavigationView, sticky header will not take effect.
If I switch TabView, sticky header will take effect again
@michael-hawker

[michael-hawker]

@zhuxb711 are you saying this is related to your original issue here or is this a different issue? We need more details to go on than a screenshot.

Can you try and modify a sample within our Sample App to reproduce the issue and paste the XAML here? (i.e. build and run sample app, open a sample, click on XAML tab, and modify code there.) That would make it a lot easier for someone to try and pick-up, diagnose the issue, and then validate a potential fix.

Thanks!

[zhuxb711]

@michael-hawker I made a sample app for you. At first, sticky header work well. If you switch the NavigationView and switch back. You will found sticky header could not work well. If you add a new tab in TabView and switch back. It works again.

TestApp.zip

[zhuxb711]

I hope that sample app will help. Thanks.