System.InvalidCastException on CollectionView enumeration

[BorzillaR]

Describe the bug

I create CollectionViewSource and enumerate items in View.

CollectionViewSource source = new CollectionViewSource() { Source = new string[] { "str1", "str2", "str3" } };
            foreach(var item in source.View) {
            }

Code failed with "System.InvalidCastException: 'Specified cast is not valid.'" exception

Exception details:

System.InvalidCastException
  HResult=0x80004002
  Message=Specified cast is not valid.
  Source=WinRT.Runtime
  StackTrace:
   at WinRT.ExceptionHelpers.ThrowExceptionForHR(Int32 hr)

Call stack:

 	winrt.runtime.dll!WinRT.ExceptionHelpers.ThrowExceptionForHR(int hr)
winrt.runtime.dll!ABI.System.Collections.Generic.IEnumerable<object>.Windows.Foundation.Collections.IIterable<object>.First()
 	winrt.runtime.dll!ABI.System.Collections.Generic.IEnumerable<object>.FromAbiHelper.GetEnumerator()
 	winrt.runtime.dll!ABI.System.Collections.Generic.IEnumerable<System.__Canon>.GetEnumerator()
 	winrt.runtime.dll!ABI.System.Collections.Generic.IList<System.__Canon>.FromAbiHelper.GetEnumerator()
 	Microsoft.WinUI.dll!ABI.Microsoft.UI.Xaml.Data.ICollectionView.GetEnumerator()
	AttachedCollections.dll!AttachedCollections.MainWindow.MainWindow() Line 19	C#

Version Info

Windows 10 1903 (OS Build 18362.1082)

NuGet package version:

WinUI 3.0.0-preview2.200713.0

Windows app type:

UWP	Win32
	Yes

Device form factor	Saw the problem?
Desktop	Yes

[StephenLPeters]

@stevenbrix is this another manifestation of the cswinrt issue?

[BorzillaR]

I have checked this issue in Preview 3 and it is still reproduced.

[stevenbrix]

@angelazhangmsft this looks like a C#/WinRT issue that was missed for Preview3. Would you mind taking a look?

[angelazhangmsft]

I'm able to repro this error with WinUI Preview 3. I also tried updating the FrameworkReference as follows and it still repros with same exception in WinRT.Runtime

<ItemGroup>
        <FrameworkReference Update="Microsoft.Windows.SDK.NET.Ref"
                            RuntimeFrameworkVersion="10.0.18362.11-preview" />
        <FrameworkReference Update="Microsoft.Windows.SDK.NET.Ref"
                            TargetingPackVersion="10.0.18362.11-preview" />
</ItemGroup>

[stevenbrix]

Thanks for clarifying, is this something that can make the first .NET5 servicing release in December?