[WinUI] C# Project Referencing a C# Library User Control failed with CS1061 and NETSDK1 errors

[XamlTest]

Describe the bug

On Visual Studio 16.11.26, add a WinUI class library to WinUI desktop project, build failed with CS1061 and NETSDK1 errors.
The test case failed on 16.11, work as expected on Visual Studio 17.7 Preview 2.
Copy the bug from [16.11] [WinUI]C# Project Referencing a C# Library User Control failed with CS1061 and CS0103 errors

Steps to reproduce the bug

Environment:
VS Build: 16.11.26
OS: Windows 10

Repo: WinUIIssues.zip

Repro Steps:

1. Create C# Blank App, Packaged (WinUI 3 in Desktop) project and rename to MyCSDesktopProject.
2. Create C# Class Library(WinUI 3 in Desktop) project and rename to MyCsClassLibrary -> Add User Control -> Add some code.
3. Focus on MyCSDesktopProject -> add existing project MyCsClassLibrary
4. Click on MyCSDesktopProject, add reference MyCsClassLibrary.
5. Build the solution.

Expected Result:
Build successfully without errors.

Actual Result:
Build failed with CS1061 and NETSDK1 errors.

Expected behavior

No response

Screenshots

No response

NuGet package version

None

Windows version

No response

Additional context

No response

[Scottj1s]

The InitializeComponent error is a known spurious issue that can be remedied with a clean rebuild. Does that unblock your scenario?

[microsoft-github-policy-service]

This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 7 days. It will be closed if no further activity occurs within 7 days of this comment.