[WASM] How to create a UNO WASM library?

[DierkDroth]

I'm trying to create a UNO WASM library but failed.

Here is what I did:

• create a UNO Platform Library using the VS2022 UNO project template
• edit Class1.cs to add a couple of UNO WASM references which work no problem in an UNO Platform App
• edit poject file
  -- remove all TargetFrameworks, only leave netstandard2.0
  -- removed ItemGroup and Conditions which are not needed
  -- added PackageReference which work well for the equivalent code in an UNO Platform App

Compiling fails, since the UNO WASM references could not be found. Repo attached

What am I doing wrong?

PlatformLibrary.zip

[jeromelaban]

Thanks for the report. When posting about build errors, post the build errors as well.

Building a WebAssembly compatible library is like creating a normal library and it only needs Uno.WinUI, and if you need to use Javascript interop, you can include Uno.Foundation.Runtime.WebAssembly.

The bootstrapper packages cannot be used here and are not needed.

[DierkDroth]

Thanks @jeromelaban. I actually built that library using your reference above.

Anyway, it's still not building after I amended the references. Please see updated repo below - binlogs within

PlatformLibrary (2).zip

[jeromelaban]

Thanks. That part is indeed not documented; you can have that type available from the Uno.WinUI.Runtime.WebAssembly nuget package.

[DierkDroth]

Thanks @jeromelaban. The repo now compiles.

[DierkDroth]

@jeromelaban sorry, but we're not done yet. I applied the changes from above to my 'real world' library project - which references a .net7.0 project and a shared project and now am getting these errors

2>C:\Users\dierk\Documents\Unusual\UnusualLibrary.Wasm\Uno.UI.SourceGenerators\Uno.UI.SourceGenerators.XamlGenerator.XamlCodeGenerator\App_0caf42f62b682314697af73203b42c5d.cs(68,91,68,115): error CS0234: The type or namespace name 'BindableMetadataProvider' does not exist in the namespace 'UnusualLibrary.Wasm' (are you missing an assembly reference?)

(binlog attached below)

Would you know what's going wrong now?

msbuild.zip

[jeromelaban]

It looks like you're trying to put App.xaml in your library, and this is not supported at this time, it needs to be in the app head.

[DierkDroth]

Thanks @jeromelaban. After restructering the solution, the library project now compiles.