Blazor WebAssembly project, Intellisense pops an error : the type or namespace name 'App' could not be found

Question

I'm trying to use Blazor WebAssembly. I create a project and the code isL

public class Program
{
    public static async Task Main(string[] args)
    {
        var builder = WebAssemblyHostBuilder.CreateDefault(args);
        builder.RootComponents.Add<App>("app"); // Error there : The type or namespace name 'App' could not be found (are you missing a using directive or an assembly reference?)

        builder.Services.AddTransient(sp => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });

        await builder.Build().RunAsync();
    }
}

As I comment in the code, App is not found by intellisense and an error is shown. I can't use f12 on the word "App" (unfound). I can build and launch the project but I want to clean it properly.

I followed this thread : Blazor the type or namespace name 'App' could not be found (are you missing a using directive or an assembly reference?) but it didn't fix it.

My IDE is Visual Studio Community : Microsoft Visual Studio Community 2019 Version 16.6.2 and dotnet --version gives : 5.0.100-preview.6.20318.15

Thank you very much.

Answer 1

make sure that all the packages using by your project has been updated and compatible with .net 5.

Updating these two packages resolved the issue for me:

Microsoft.AspNetCore.Components.WebAssembly Microsoft.AspNetCore.Components.WebAssembly.DevServer