Using Uno.Sdk get the error of error UNOB0008: Building a WinUI class library with dotnet build is not supported when XAML files are present. Use msbuild instead.

[cconner100]

Migrating my code to the new Uno.Sdk csproj format. I get the following error some of my dll support projects of error UNOB0008: Building a WinUI class library with dotnet build is not supported when XAML files are present. Use msbuild instead.

my new csproj looks like this

<Project Sdk="Uno.Sdk">
  <PropertyGroup>
	  <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('windows')) or '$(EnableWindowsTargeting)' == 'true'">net8.0-windows10.0.22621</TargetFrameworks>
	  <!-- Unused frameworks net8.0-browserwasm;net8.0-desktop -->
	  <TargetFrameworks>
		  net8.0;
		  net8.0-ios;
		  net8.0-maccatalyst;
		  net8.0-android;
		  $(TargetFrameworks);
	  </TargetFrameworks>
    <UnoSingleProject>true</UnoSingleProject>
    <OutputType>Library</OutputType>
    <!-- Ensures the .xr.xml files are generated in a proper layout folder -->
    <GenerateLibraryLayout>true</GenerateLibraryLayout>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>

    <!--
      UnoFeatures let's you quickly add and manage implicit package references based on the features you want to use.
      https://aka.platform.uno/singleproject-features
    -->

    <UnoFeatures>
		Navigation;
		Hosting;
		Extensions;
		MauiEmbedding;
	</UnoFeatures>

  </PropertyGroup>

  <ItemGroup Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'windows'">
    <!--
    If you encounter this error message:

      error NETSDK1148: A referenced assembly was compiled using a newer version of Microsoft.Windows.SDK.NET.dll.
      Please update to a newer .NET SDK in order to reference this assembly.

    This means that the two packages below must be aligned with the "build" version number of
    the "Microsoft.Windows.SDK.BuildTools" package above, and the "revision" version number
    must be the highest found in https://www.nuget.org/packages/Microsoft.Windows.SDK.NET.Ref.
    -->
    <!-- <FrameworkReference Update="Microsoft.Windows.SDK.NET.Ref" RuntimeFrameworkVersion="10.0.22621.28" />
    <FrameworkReference Update="Microsoft.Windows.SDK.NET.Ref" TargetingPackVersion="10.0.22621.28" /> -->
  </ItemGroup>

	<ItemGroup>

		<PackageReference Include="Microsoft.Extensions.Logging.Console" />
		<PackageReference Include="Microsoft.Graph" />

		<PackageReference Include="Microsoft.Extensions.DependencyInjection" />

		<PackageReference Include="Microsoft.Extensions.Http" />
		
		<!-- Community Toolkit stuff -->
		<PackageReference Include="CommunityToolkit.Mvvm" />
		<PackageReference Include="CommunityToolkit.WinUI.Animations" />
		<PackageReference Include="CommunityToolkit.WinUI.Controls.SettingsControls" />

	</ItemGroup>

	<ItemGroup>
	  <ProjectReference Include="..\..\..\Framework\Client\ZtClientFramework.Maui\ZtClientFramework.Maui.csproj" />
	  <ProjectReference Include="..\..\..\Framework\Client\ZtClientFramework\ZtClientFramework.csproj" />
	  <ProjectReference Include="..\..\..\Framework\Shared\ZtFramework\ZtFramework.csproj" />
	</ItemGroup>

	<ItemGroup>
	  <Page Update="TestViews\HomePage.xaml">
	    <Generator>MSBuild:Compile</Generator>
	  </Page>
	</ItemGroup>
</Project>

[jeromelaban]

Thanks for the report. The error really means what it says, this is a winui issue for building apps with dotnet build. You may be getting this error on CI, or using the command line. Using msbuild will fix the error.

[lindexi]

@jeromelaban May I know which winui issue it is? Thank you.

Is it microsoft/WindowsAppSDK#3548 ?

Such as C:\Users\dev\.nuget\packages\microsoft.windowsappsdk\1.2.221209.1\buildTransitive\MrtCore.PriGen.targets(911,5): error MSB4062: The "Microsoft.Build.Packaging.Pri.Tasks.ExpandPriContent" task could not be loaded from the assembly C:\Program Files\dotnet\sdk\7.0.300-preview.23179.2\\Microsoft\VisualStudio\v17.0\AppxPackage\\Microsoft.Build.Packaging.Pri.Tasks.dll. Could not load file or assembly 'C:\Program Files\dotnet\sdk\7.0.300-preview.23179.2\Microsoft\VisualStudio\v17.0\AppxPackage\Microsoft.Build.Packaging.Pri.Tasks.dll'. The system cannot find the path specified. Confirm that the <UsingTask> declaration is correct, thatthe assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask. [C:\Users\dev\WinPublish\WinPublish.csproj] ?

[jeromelaban]

Yes it is, you can see more details here: https://platform.uno/docs/articles/uno-build-error-codes.html#unob0008-building-a-winui-class-library-with-dotnet-build-is-not-supported.

[lindexi]

Thank you very much. I find your solution in #16500 (comment)