[Blazor] Errors in the startup project

[Ratomir]

Error in the startup project

I have errors, but still, I can compile and run the code without any issues.

To Reproduce

Steps to reproduce the behavior:

1. Install ASP.NET core version, 3.1.0-preview1.19508.20
2. Install the last update of Visual Studio, my version 16.4.0 Preview 2.0
3. Create a new Blazor WebAssembly project with the latest Blazor project template in the empty solution
4. Open the SurveyPrompt.razor page in the Shared folder of the new application
5. You will see three types of errors

• CS0111 Type 'SurveyPrompt' already defines a member called 'BuildRenderTree' with the same parameter types, Line 1

• CS0102 The type 'SurveyPrompt' already contains a definition for 'Title' Line 15

• CS0229 Ambiguity between 'SurveyPrompt.Title' and 'SurveyPrompt.Title'

Expected behavior

Open and see razor files without any issues and clear "Error List" tab of the Visual Studio

Screenshots

See the screenshot.

Here is the list of all nuget packages.

Additional context

If I open the compiled file in the background of the razor file and add a partial class keyword in the name of the class, errors will disappear.

This could be related to this feature, about partial class, https://devblogs.microsoft.com/aspnet/asp-net-core-updates-in-net-core-3-1-preview-1/

Thanks,
Ratomir

[Ratomir]

More details, I did changes on the Counter page and made a new C# class, Couter.razor.cs. Two errors disappeared, but still, I have a one about BuildRenderTree. Screenshot below:

[Ratomir]

Huh, I found what was the issue. I had a global.json file with the specified sdk version, for some reason, that file has been copied when I create a new project. Anyway, I deleted this file and everything working properly. I will close the issue.