Creating Winforms application with errors and targeting is still 6.0 by CLI after installing the latest .Net 7.0 SDK build

[Olina-Zhang]

.NET Core Version:

.Net SDK 7.0.100-alpha.1.21527.14

More Info:

This issue can also reproduce when creating WPF, console application by CLI

To Reproduce

1. Install the latest .Net 7.0 SDK build from main branch in https://github.com/dotnet/core-sdk
2. Create winforms application by CLI: donet new winforms
3. Open application's csproj file to check TargetFramework

Actual result:

In step2, create app successfully with some errors by CLI

In step3, the application's TargetFramework is still 'net6.0-windows', not 7.0

Expected result:

Creating application by CLI successfully with no any errors and TargetFramework is right version 'net7.0-windows'

[marcpopMSFT]

7.0 templates need to be updated to target 7.0

[EmilyFeng97]

This issue also repro when creating the asp.net core app.

[dreddy-work]

#6206