The latest version of Blazor is based .NET Core 3 which is only supported in VS 19.

But the extension https://marketplace.visualstudio.com/items?itemName=aspnet.blazor won’t install in my VS2017 (Enterprise). However when installed using CLI it works:
“dotnet new -i Microsoft.AspNetCore.Blazor.Templates::3.0.0-preview6.19307.2”

Still the templates won’t display on the New Project. You must use the CLI to create a new Blazor project:
“dotnet new blazorserverside”
or “dotnet new blazorhosted”
or “dotnet new blazorlib”
or “dotnet new blazor”

The project won’t build or run in the VS2017 IDE. Again, you must use the CLI:
“dotnet build”
“dotnet run”

Thanks for the prompt reply.

after reading the link mentioned by you, I just changed calculator.cshtml to calculator.razor and calculator is working fine now.

regards

There are some breaking changes in the latest version of Blazor. This can be the reason for this error. You can see the list of changes at https://devblogs.microsoft.com/aspnet/asp-net-core-and-blazor-updates-in-net-core-3-0-preview-6/. Update your code accordingly and see if the issue is resolved. If the issue persists, post it on SO. If someone has faced the similar problem they will reply to it.

I read this nice article and also tried my self. I have installed VS 2019 preview community edition for learning purpose.

I write my code as well as tried your one, but I got the following error message in both

“Cannot convert method group ‘AddNumbers’ to non-delegate type ‘object’. Did you intend to invoke the method?

VS give me this error on every method, even on his own function “@IncrementCount”.

Please advice the suitable solution.

Thanks & Best Regards