[MAUI][Multi-Project] Downloading the .NET9.0 SDK causes the original .NET8.0 SDK to disappear when creating a project

[XamlTest]

Description

Creating a .NET MAUI Multi-Project App project and downloading the .NET9.0 SDK causes the original .NET8.0 SDK to disappear when creating the project.

Steps to Reproduce

1.Download SDK .NET9.0-Preview.3 (Download .NET 9.0 (Linux, macOS, and Windows) (microsoft.com))
2.Run the "dotnet workload install maui" in cmd to installer the Maui template
3.Launch the VS
4.Create a .NET MAUI Multi-Project App
Actual Result:
In Additional information, NET 9.0 (preview) only in the framework drop-down menu.

Expected Result:
.NET MAUI multi-project app should display .NET8.0 and .NET9.0 SDKs.

More information: In the .net Maui App, .NET MAUI Blazor Hybrid App and .NET Maui Class Library projects can display .net8.0 and .net9.0 SDKs.

Link to public reproduction project repository

No response

Version with bug

Unknown/Other

Is this a regression from previous behavior?

No, this is something new

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

Windows10.0.19041.0

Did you find any workaround?

No response

Relevant log output

No response

[github-actions]

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[RoiChen001]

Can repro this issue on the latest 17.10 Preview 7(.NET SDK: 9.0.100-preview.3.24204.13).

[TommiGustafsson-HMP]

We had a similar issue with .NET SDK 9.0 Preview 2 disappearing, when .NET SDK 9.0 Preview 3 was installed. However, we could just re-install Preview 2, but that was weird.

[marcpopMSFT]

@phenning We don't have the 9.0 SDK inserted into VS yet. I'm surprised though that installing the 9 previews makes the 8 targeting disappear from NPE.

[phenning]

@marcpopMSFT looking at the title and screenshots, it looks like the .NET MAUI MultiProject tempate was just added for NET 9.0. All the other listed templates are behaving as expected (showing both net8.0 and net9.0)

(See history here: https://github.com/dotnet/maui/commits/main/src/Templates/src/templates/maui-multiproject/.template.config/template.json

This is by design unless the template was added to a servicing release of the net 8.0 workload.

[marcpopMSFT]

Ahh, I didn't realize this was a new template. Makes sense then to me.