Uno.Sample.ControlLibrary.Wasm - The target "Build" does not exist in the project

[MelbourneDeveloper]

When I try to build Uno.Sample.ControlLibrary.Wasm in VS 2017 15.9.12, I get

Severity Code Description Project File Line Suppression State
Error MSB4057 The target "Build" does not exist in the project. XamlControlLibrary C:\Code\Uno.Samples\UI\ControlLibrary\XamlControlLibrary\XamlControlLibrary.csproj 1

[MelbourneDeveloper]

On Mac:

/Users/CFindlay/.nuget/packages/uno.sourcegenerationtasks/1.22.0-dev.32/build/net45/Uno.SourceGenerationTasks.targets(3,3): Error MSB4062: The "Uno.SourceGeneratorTasks.SourceGenerationTask_v5d0923b6b600ebff51ba20c89e08ae2d6ce32e5a" task could not be loaded from the assembly /Uno.SourceGeneratorTasks.v5d0923b6b600ebff51ba20c89e08ae2d6ce32e5a.dll. Invalid Image Confirm that the declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask. (MSB4062) (XamlControlLibrary)

[ahmedaniss25]

i fix this problem here : https://www.youtube.com/watch?v=_Jl0q5U3R1A you can follow my step to fix this problem .

YouTube

How To Export Unity Games To WebGl

suggestion words : build.wasm does not exist build.temp.asm.js does not exist

[hawkerm]

I find that I have to build the UWP head manually first before the WASM builds, but then with a fresh clone of the current repo, I still get this error trying to run the WASM head:

System.InvalidOperationException: The SPA default page middleware could not return the default page '/index.html' because it was not found, and no other middleware handled the request.

   at Microsoft.AspNetCore.SpaServices.SpaDefaultPageMiddleware.<>c__DisplayClass0_0.<Attach>b__1(HttpContext context, Func`1 next)
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Builder.Extensions.MapWhenMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

[jeromelaban]

This issue is fixed since Uno 4.0