The type or namespace name 'WeatherForecastService' could not be found (are you missing a using directive or an assembly reference?)

[donhuvy]

I am using ASP.NET Core Blazor WebAssembly version 5 with Individual security, Microsoft Visual Studio Community 2019 Version 16.8.3, .NET 5 version 5.0.101, Windows x64 version 2004, DevExpress Blazor web-assembly version 20.0.4 .

If I don't copy view files to directory Client project \ Pages , I did not catch any error (Not show error missing a using directive or an assembly reference...).

But when I copy a directory a1(https://github.com/donhuvy/a2021/tree/main/Client/Pages/a1) with many views pages, I catch error

The type or namespace name 'WeatherForecastService' could not be found (are you missing a using directive or an assembly reference?)

The behavior is very strange. What is the cause of error?

(full project with compiled thing https://1drv.ms/u/s!AhMAe-fS33VbkGEDvHkEM4lwmpax?e=Yx2ELH)

https://i.stack.imgur.com/JStf2.png

Please help me answer this question.

https://stackoverflow.com/questions/65522578/the-type-or-namespace-name-weatherforecastservice-could-not-be-found-are-you

[donhuvy]

please delete my question.