Nukepayload2.UI.VBWinUI3.XamlCompiler 3.0.0-dev

Nukepayload2.UI.VBWinUI3.XamlCompiler

A compiler-only replacement for the XAML compiler binaries that ship inside Microsoft.WindowsAppSDK.WinUI. Built from winui3-vbxamlc, a fork of microsoft-ui-xaml whose Visual Basic code generators are fixed: with DISABLE_XAML_GENERATED_MAIN defined they emit XamlGeneratedProgram.XamlGeneratedMain() plus the two-layer XamlGeneratedCreateApplicationInstance hooks that the stock compiler does not produce for VB.

The package contains only the compiler binaries. The MSBuild targets, genxbf and the reference assemblies keep coming from Microsoft.WindowsAppSDK; three properties are redirected:

NuGet imports the props through obj\<project>.nuget.g.props, which is evaluated before the empty-value guards in the stock Microsoft.UI.Xaml.Markup.Compiler.interop.targets, so these assignments win.

Usage

<ItemGroup>
  <PackageReference Include="Nukepayload2.UI.VBWinUI3.XamlCompiler" Version="3.0.0-dev" />
</ItemGroup>

DevelopmentDependency=true keeps the package private, so no PrivateAssets / ExcludeAssets are needed - adding them would also suppress the buildTransitive import that does the override.

To use the stock compiler instead:

dotnet build -p:VBWinUI3XamlCompilerEnabled=false

Verifying which compiler ran

1. The build log contains VBWinUI3 XamlCompiler override active: … with all three paths under ~\.nuget\packages\nukepayload2.ui.vbwinui3.xamlcompiler\<version>\tools\.
2. The generated App.g.i.vb contains Friend Module XamlGeneratedProgram and Sub XamlGeneratedMain().
3. Every generated file carries GeneratedCodeAttribute("Microsoft.UI.Xaml.Markup.Compiler", " 3.0.0.0"); the stock 2.2.x compiler stamps 3.0.0.2606.

Incremental builds decide whether to re-run XAML compilation from a fingerprint of the XAML files, references and local assemblies, not of the compiler binaries: delete obj\ and bin\ after switching or repacking the compiler.

Repacking

:: 1. build the compiler in Release (writes BuildOutput\packaging\Release\tools)
Build.cmd product

:: 2. pack into ..\..\PackageStore
build\xamlcompiler-nupkg\pack.cmd

~\.nuget\packages\<id>\<version> is immutable to NuGet, so a repacked version is ignored in favour of the cached copy. Bump the version (pack.cmd -p:PackageVersion=3.0.0-dev.1) or delete the cached folder and restore again.

Differences from the stock tools

• The Core-MSBuild tool folder is tools\net8.0\ instead of tools\net6.0\; the file names are the same.
• Only the three binaries above are replaced. The fork's interop.targets also passes EnabledXamlOptionalChanges / DisabledXamlOptionalChanges; that file is not shipped, so those properties stay empty (their default), which only affects the C#/C++ generators.