Invalid cref value "!:XElement"

[Weasy666]

Operation System: (Windows or Linux or MacOS)
Azure Pipelines...i guess Windows.

DocFX Version Used:
Don't know what version is used by MixedReality Toolkit.

Steps to Reproduce:

1. Create some triple slash comment with a cref to an XElement.
2. Build docs with this config

Expected Behavior:
XElement will get referenced.

Actual Behavior:
Invalid cref value "!:XElement" found in triple-slash-comments for AddCapability, ignored.

For more details you can take a look here microsoft/MixedRealityToolkit-Unity#5891 (comment)

[superyyrrzz]

Can Visual Studio find this type, or also complain about a warning?

[Weasy666]

There is no problem in Visual Studio. The type is a regular Microsoft type XElement. If you take a look at the MixedReality Toolkit link you can see that the error does not only occur for XElement but also for XAttribute and XName. So i guess there is maybe a general problem with the System.Xml.Linq Namespace.

[superyyrrzz]

I had a peek at the repo, but did not find any existing .csproj/.sln to help me see its behavior in Visual Studio.
BTW, have you tried the full name System.Xml.Linq.XElement?

[Weasy666]

No, i haven't tried that. I'm a first time contributer to that project so i'm not in a position to try that. But maybe @wiwei can try?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in a week if no further activity occurs.

[tparviainen]

I'm seeing similar issue with my .NET Standard assembly, however I also found the workaround for this issue. Here are the repro steps:

git clone https://github.com/tparviainen/clashofclans.git clash1
cd clash1/docfx
docfx

That generates several warning messages about Invalid cref value "!:System.ArgumentException" found in triple-slash-comments.

If you instead do next steps you do not see those warning messages:

git clone https://github.com/tparviainen/clashofclans.git clash2
cd clash2/docfx
dotnet build ../src/ClashOfClans/ClashOfClans.csproj
docfx

So it seems that if the component is first compiled and after that the documentation is generated by DocFX the issue is not present.

[koffie]

I verified @tparviainen his solution and worked for my project. I think this van be closed.

[martinoss]

In my case, a wrong target framework configured in docfx.json. I copied it from a 4.7.2 project, but the new one had netstandard2.0.
But I additionally got the warning The "ResolvePackageAssets" task failed unexpectedly. NuGet.Frameworks.FrameworkException: Invalid framework identifier ''.