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Microsoft.NET.Sdk.WebAssembly: Guidance on inheriting Static Web Assets from Library projects or Nuget packages #54597

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Microsoft.NET.Sdk.WebAssembly: Guidance on inheriting Static Web Assets from Library projects or Nuget packages#54597
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@invino4

Description

@invino4
invino4
opened on Jun 4, 2026

Describe the bug

When leveraging Microsoft.NET.Sdk.WebAssembly to create a WASM-only project (No Blazor) that also takes a dependency on a standard Library project (using Microsoft.NET.Sdk) which in turn contains its own static web assets, it is unclear how to export the static web assets such that they properly appear both:

  1. When published (dotnet publish).
  2. When debugging (either dotnet run or F5 in Visual Studio).

While the Microsoft.NET.Sdk.WebAssembly default debug experience appears to leverage the SWA pipeline available to Blazor apps, it does not seem to include static web assets from the dependent libraries, nor does it take any notice of the <StaticWebAssetBasePath> that appears in those libraries.

The static web asset files can be explicitly binplaced with <Content> in the Library to get the proper publish behavior, but ONLY by manually creating any nested library-specified content paths within the library's file structure. This is undesirable because it creates extra directory structure that is not normally present.

Or in the alternative the app project can explicitly include content from the library using its own <Content Include="..\MyLibrary\wwwroot\**\*" Link="wwwroot\MyLibrary\%(RecursiveDir)%(Filename)%(Extension)"> pattern. This allows the app to define the substructure but requires the app to know about the make-up of its library a priori (e.g. whether or not they even have static web assets) breaking project independence.

The above solutions produce a proper binplaced file layout for Publish. However, neither of the above solutions correctly participates in the SWA pipeline that generates the static web asset manifest leveraged by the default debugging experience. dotnet run and F5 in Visual Studio include ONLY the assets found directly in the app's wwwroot and do NOT include those assets inherited from dependencies.

What is the proper way to build this two-project solution such that publishing and debugging work correctly?

Steps to reproduce

MyLibrary.csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net10.0-browser</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>

    <!-- Needed for [JSImport]. -->
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>

    <StaticWebAssetBasePath>MyLibrary</StaticWebAssetBasePath>
  </PropertyGroup>

  <ItemGroup>
    <Content Include="wwwroot\**\*" CopyToOutputDirectory="Always" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.JSInterop" Version="10.0.8" />
  </ItemGroup>

</Project>

MyWasm.csproj

<Project Sdk="Microsoft.NET.Sdk.WebAssembly">
  <PropertyGroup>
    <TargetFramework>net10.0-browser</TargetFramework>
    <Nullable>enable</Nullable>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>

  <!-- Include SWA assets from MyLibrary? -->
  <ItemGroup>
    <!--<Content Include="..\MyLibrary\wwwroot\**\*" 
             Link="wwwroot\MyLibrary\%(RecursiveDir)%(Filename)%(Extension)" 
             CopyToOutputDirectory="Always" />-->
  </ItemGroup>


  <ItemGroup>
    <PackageReference Include="Microsoft.JSInterop.WebAssembly" Version="10.0.8" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\MyLibrary\MyLibrary.csproj" />
  </ItemGroup>
</Project>

Expected behavior

The MyWasm project to automatically include the static web assets defined in MyLibrary. Those assets are available at runtime at an offset path defined by the <StaticWebAssetBasePath> tag in MyLibrary. Those assets are binplaced to the appropriate file structure by Publish. Those assets are included (referenced from their original location within the project directory of MyLibrary) in the SWA manifest produced by the MyWasm build and used to load static web assets during debugging sessions (either dotnet run or F5 in Visual Studio).

Actual behavior

The static web assets from MyLibrary are not available to the app under test during debugging sessions (either dotnet run or F5 in Visual Studio). The static web assets are only published IFF CopyToOutputDirectory="Always" is explicitly specified in the <Content>.

Is this a regression?

n/a

Are there any workarounds?

The static web assets from MyLibrary can be explicitly copied into the wwwroot folder of MyWasm before building. This makes maintenance complicated, but it does work.

dotnet --info output

D:\dev\Wasm\WasmBrowser >dotnet --info
.NET SDK:
 Version:           10.0.300
 Commit:            caa81fa497
 Workload version:  10.0.300.3
 MSBuild version:   18.6.3+caa81fa49

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19045
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\10.0.300\

.NET workloads installed:
 [android]
   Installation Source: SDK 10.0.300, VS 17.14.37301.10, VS 18.6.11822.322
   Manifest Version:    36.1.53/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.android\36.1.53\WorkloadManifest.json
   Install Type:              Msi

 [ios]
   Installation Source: SDK 10.0.300, VS 17.14.37301.10, VS 18.6.11822.322
   Manifest Version:    26.5.10284/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.ios\26.5.10284\WorkloadManifest.json
   Install Type:              Msi

 [maccatalyst]
   Installation Source: SDK 10.0.300, VS 17.14.37301.10, VS 18.6.11822.322
   Manifest Version:    26.5.10284/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.maccatalyst\26.5.10284\WorkloadManifest.json
   Install Type:              Msi

 [macos]
   Installation Source: SDK 10.0.300
   Manifest Version:    26.5.10284/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.macos\26.5.10284\WorkloadManifest.json
   Install Type:              Msi

 [maui-windows]
   Installation Source: SDK 10.0.300, VS 17.14.37301.10, VS 18.6.11822.322
   Manifest Version:    10.0.20/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.maui\10.0.20\WorkloadManifest.json
   Install Type:              Msi

 [wasm-experimental]
   Installation Source: SDK 10.0.300
   Manifest Version:    10.0.108/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.workload.mono.toolchain.current\10.0.108\WorkloadManifest.json
   Install Type:              Msi

 [wasm-tools]
   Installation Source: SDK 10.0.300
   Manifest Version:    10.0.108/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.workload.mono.toolchain.current\10.0.108\WorkloadManifest.json
   Install Type:              Msi

Configured to use workload sets when installing new manifests.

Host:
  Version:      10.0.8
  Architecture: x64
  Commit:       94ea82652c

.NET SDKs installed:
  1.0.4 [C:\Program Files\dotnet\sdk]
  2.1.104 [C:\Program Files\dotnet\sdk]
  2.1.202 [C:\Program Files\dotnet\sdk]
  2.1.302 [C:\Program Files\dotnet\sdk]
  2.1.401 [C:\Program Files\dotnet\sdk]
  2.1.526 [C:\Program Files\dotnet\sdk]
  2.1.818 [C:\Program Files\dotnet\sdk]
  2.2.103 [C:\Program Files\dotnet\sdk]
  3.0.103 [C:\Program Files\dotnet\sdk]
  3.1.120 [C:\Program Files\dotnet\sdk]
  3.1.426 [C:\Program Files\dotnet\sdk]
  5.0.101 [C:\Program Files\dotnet\sdk]
  5.0.104 [C:\Program Files\dotnet\sdk]
  5.0.202 [C:\Program Files\dotnet\sdk]
  5.0.214 [C:\Program Files\dotnet\sdk]
  5.0.303 [C:\Program Files\dotnet\sdk]
  5.0.406 [C:\Program Files\dotnet\sdk]
  5.0.408 [C:\Program Files\dotnet\sdk]
  7.0.410 [C:\Program Files\dotnet\sdk]
  8.0.127 [C:\Program Files\dotnet\sdk]
  9.0.305 [C:\Program Files\dotnet\sdk]
  9.0.314 [C:\Program Files\dotnet\sdk]
  10.0.108 [C:\Program Files\dotnet\sdk]
  10.0.300 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.27 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 9.0.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 10.0.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 1.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 1.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.23 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.27 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 9.0.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 10.0.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.0.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.14 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.23 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.15 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 8.0.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 8.0.27 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 9.0.16 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 10.0.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  arm64 [C:\Program Files\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\arm64\InstallLocation]
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

IDE version

Visual Studio 2026

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