[Bug] After #7531 some XAML namespaces require assembly

[VitalyKnyazev]

Description

Ironically after #7531 some XAML namespaces require assembly name otherwise the app just crashes.

Steps to Reproduce

1. Add a XAML element like Button and set its Text to a string property of a static class like
   "public static class ResourceStrings", for example Text="{x:Static resources:ResourceStrings.SomeText}"
2. Namespace xmlns:resources="clr-namespace:App.Core" worked ok before 4.3.0.851321-pre3
3. Now namespace like xmlns:resources="clr-namespace:App.Core;assembly=App.Portable" is necessary to avoid the crash.

Expected Behavior

xmlns:resources="clr-namespace:App.Core" should be enough

Actual Behavior

The app crashes unless assembly is specified
xmlns:resources="clr-namespace:AppCore;assembly=App.Portable"

Basic Information

• Version with issue: 4.3.0.851321-pre3
• Last known good version: 4.3.0.819712-pre2
• IDE: VS2019 16.3.2
• Platform Target Frameworks:
  • iOS: 13.2.0.42
  • Android: 10.0.0.43

[PureWeen]

@StephaneDelcroix

[StephaneDelcroix]

please provide a repro project as soon as you can. thanks

[VitalyKnyazev]

Hi @StephaneDelcroix

Here is the project:
https://github.com/VitalyKnyazev/StaticCrash

It is a bit trickier than I thought:

• x:Static must be within DataTemplate
• XamlCompilation must be off

If you change
xmlns:core="clr-namespace:StaticCrash"
to
xmlns:core="clr-namespace:StaticCrash;assembly=StaticCrash"
then it also works.

Off topic - is it worth turning off XAML compilation in DEBUG mode?

[StephaneDelcroix]

Thanks, will look at that.

Off topic - is it worth turning off XAML compilation in DEBUG mode?

well, yes and no

yes:

• (1) it speeds up the dev cycle

no:

• (2) you'll miss a lot of error usually caught at compile-time with XamlC on
• (3) the application you're currently debugging is not the same that the one you'll release, and you have to make sure you're testing it in Release mode as well (this is always a good advice, btw)

To get the gain from (1), and keep the validation, we introduced a new flag that only does the validation part, but doesn't actually write the assembly back (#7407). This will be available in 4.3. We're still considering enabling that by default.