Self-contained component targets expose runtime payloads as project items during DesignTimeBuild

[Illustar0]

Describe the bug

When an executable SDK-style project references a Windows App SDK component package such as Microsoft.WindowsAppSDK.WinUI, the component package enables WindowsAppSDKSelfContained by default.

Microsoft.WindowsAppSDK.SelfContained.targets then adds all files under runtimes-framework\win-<arch>\native and metadata to the None item group with Link metadata.

These items are also created during DesignTimeBuild. IDEs that consume the resulting MSBuild project model, such as JetBrains Rider, display hundreds of runtime DLLs, MUI directories, assets, and WinMD files as linked project files.

For example:

• af-ZA\Microsoft.ui.xaml.dll.mui
• metadata\Microsoft.Windows.AppLifecycle.winmd
• Microsoft.UI.Xaml.Controls.dll

This makes Solution Explorer extremely large.

Steps to reproduce the bug

Create an SDK-style project:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0-windows10.0.26100.0</TargetFramework>
    <RuntimeIdentifier>win-x64</RuntimeIdentifier>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference
        Include="Microsoft.WindowsAppSDK.WinUI"
        Version="1.8.250906003" />
  </ItemGroup>
</Project>

Open the project in JetBrains Rider and expand it in Solution Explorer.

Expected behavior

Runtime payload files required for self-contained deployment should be copied during normal build/publish, but should not be exposed as source project items during DesignTimeBuild.

Screenshots

NuGet package version

1.8.250831001

Packaging type

Unpackaged

Windows version

Windows 11 version 24H2 (26100, June 2025 Update)

IDE

Other

Additional context

No response

[lauren-ciha]

Thank you for filing an issue! I was not able to reproduce this in Visual Studio. This could be an DesignTimeBuild implementation difference in JetBrains Rider (external to the Windows App SDK). Manodasan Wignarajah (@manodasanW) Scott Jones (@Scottj1s), what are your thoughts?

[Illustar0]

I can confirm that I am not seeing this behavior in Visual Studio, so this appears to be related to how Rider consumes or presents the DesignTimeBuild project model.

The Windows App SDK targets still add the runtime payloads to the None item group during DesignTimeBuild, but Visual Studio seems to filter or hide those items, while Rider displays them as linked project files.

I am currently using the following workaround to remove these items from the DesignTimeBuild project model:

<PropertyGroup>
  <CustomAfterMicrosoftCommonTargets>
    $(MSBuildThisFileDirectory)BetterWinUI.AfterCommon.targets
  </CustomAfterMicrosoftCommonTargets>
</PropertyGroup>

<Project>
  <Target
      Name="RemoveWindowsAppSDKPayloadFilesFromDesignTimeBuild"
      AfterTargets="AddMicrosoftWindowsAppSDKPayloadFilesFromComponents"
      Condition="'$(DesignTimeBuild)' == 'true'">
    <ItemGroup>
      <None Remove="@(MicrosoftWindowsAppSDKFiles)" />
    </ItemGroup>
  </Target>
</Project>

This resolves the issue in Rider without affecting normal build or publish behavior.

I will also report this to JetBrains, since Rider likely should not display these deployment payloads as regular project files. However, avoiding the creation of these None items during DesignTimeBuild would also make the targets less dependent on IDE-specific filtering behavior.