Combobox disappears when reopened

[headslash]

Current behavior

Opening Combobox with Binding in Itemsource works like it should. Dropdown opens with all options. You select one, it binds back like it should.
You reopen it to select something else and...
The whole view that it is in disappears. There is no way other than resetting the application or reloading it to reset it.

I found it while working on a bigger application that uses smaller generated views that could include comboboxes. in those cases it would delete the childview altogether.

I replicated in a minimalistic/same enviroment in the MainPage.
Both the combobox with or without binding has the same issue.

This is in .net7.

recreating this in .net6 does not give the same issue.

Expected behavior

Using a combobox for a second time works like it should, not removing the view altogether

How to reproduce it (as minimally and precisely as possible)

UnoApp1 - example.zip

Workaround

Instead of using

<ComboBox ItemsSource="{x:Bind Title}"/>

using

<ComboBox Grid.Row="3">  
            <ComboBoxItem>ComboBox Item #1</ComboBoxItem>
            <ComboBoxItem IsSelected="True">ComboBox Item #2</ComboBoxItem>
            <ComboBoxItem>ComboBox Item #3</ComboBoxItem>
</ComboBox>

Does work but bindings are not really an option in my case.

Works on UWP/WinUI

None

Environment

Uno.UI / Uno.UI.WebAssembly / Uno.UI.Skia

NuGet package version(s)

all current updated stable versions
no extra ones

Unoplatform extension 4.9.12.12
using .net7

Affected platforms

WebAssembly, Skia (WPF), Skia (GTK on Linux/macOS/Windows)

IDE

Visual Studio 2022

IDE version

17.6.2

Relevant plugins

none

Anything else we need to know?

No response

[jeromelaban]

Thanks for the report. In the repro sample you're providing, you're using a string as the input, and this is not supported by WinUI.

Is your original issue using the same "string" binding as the item source?

[headslash]

The string binding was just a simple way to make an example because it has the exact same response as the other inputs.
which are string[] (at the start of the project for simplicity) and later ObservableCollection.
In both cases I have problems with the disappearing Views.

I also tested both Binding and x:Bind but those still gave the issue regarding the disappearing views while still functioning properly.

Would you like me to include an example project with those other inputs?

[headslash]

I'm an idiot, sorry first time doing a propper issue, This is not professional. My bad.

[jeromelaban]

No worries about closing the issue :)

Are you able to reproduce the issue with the Uno Playground? Here's an example: https://playgroundcanary.z19.web.core.windows.net/#combobox

[headslash]

I'm unable to reproduce it uno playground, I tried that yesterday to be sure. I also copied the xaml into VS22 in my uno enviroment (.net7) and it has the same problem. I tried it in the .net6 test project and it works just fine.

[jeromelaban]

Thanks. To be sure, you're testing in WebAssembly, specifically?

[headslash]

in both webassembly and skia.wpf.
Both have the issue

[jeromelaban]

Thanks for the update.

Note for contributors

It seems that for some reason, the contents of the Frame is getting cleared when opening the popup for the second time. This does not repro in the playground (http://playground.platform.uno/#ef1ff7f8). It is not related to x:Bind nor material theming.

[jeromelaban]

@headslash the piece of the code that cause the issue to happen is the DataContext = this line. If you're using x:Bind you should not need this particular statement and it will work around the issue.