.NET 9.0 project form designer does not load properly after downloading the latest .NET 10.0 sdk in VS main.

[Philip-Wang01]

.NET version

.NET SDK 10.0.100-alpha.1.24570.22

Did it work in .NET Framework?

Yes

Did it work in any of the earlier releases of .NET Core or .NET 5+?

Yes, this is a regression issue. It also works fine on .NET 10.0.100-alpha.1.24561.7.

Issue description

VS	Default .NET 9.0 version	.NET 10.0 version	Result
17.13.0 Preview 2.0 (latest main)	9.0.200-preview.0.24519.19	10.0.100-alpha.1.24570.22(latest sdk)	.NET 9.0 project form designer does not load properly
17.13.0 Preview 2.0 (latest main)	9.0.200-preview.0.24519.19	10.0.100-alpha.1.24561.7	.NET 9.0 Project forms designer loads properly
17.12.1	9.0.100	10.0.100-alpha.1.24570.22	.NET 9.0 Project forms designer loads properly
17.13.0 Preview 1.0	9.0.100-rc2.24474.11	10.0.100-alpha.1.24570.22	.NET 9.0 project form designer does not load properly

More Info:

1. verbose_log.txt
2. This issue is not reproduced in .NET 6.0 and .NET 8.0 projects.
3. This issue is also reproduced in the WPF project.
   

Steps to reproduce

1. Install the latest build of VS and the latest build of .NET 10.0.
2. Create a .NET 9.0 WinForms project and observe the results.

[merriemcgaw]

@Philip-Wang01 does this impact non WindowsDesktop apps, like console apps?

[chaowendy]

Verified this issue on VS latest build: Version 17.13.0 Preview 3.0 [35526.105.main]&17.13 Preview 1, the issue does not repro. After downloading the latest .NET 10.0 SDK , .NET 9.0 project form designer can load properly in VS main. So, close the issue.