Converting the source tree to WinUI

The current Uno source tree is based on UWP, and the CI uses a specific step to generate the WinUI 3.0 compatible API set, and the associated packages.

Using the auto-generated synchronized branch

The Uno CI automatically maintains a WinUI-converted branch of the tree after every push to tracked branches, in order to get started faster when debugging WinUI related issues.

The branch is maintained as follows:


You can checkout this branch locally to get started faster.

The conversion process

The conversion process is done as follows, from a clean repository:

  • The Uno.WinUIRevert is removing and moving folders from the UWP structure to adjust to the WinUI structure
  • The Uno.UWPSyncGenerator is run to regenerate the whole WinRT/WinUI 3.0 API set
  • A set of nuspec conversions are performed in build\Uno.UI.Build.csproj in the BuildNuGetPackage target

To ease the adjustments when conversion issues arise:

  • The UNO_UWP_BUILD msbuild variable is set to true when the tree is "UWP" mode, and undefined when the tree is in WinUI mode.
  • The HAS_UNO_WINUI C# constant is defined when the tree is built in WinUI mode.

Converting a local source tree

The conversion process can be run locally as follows:

  • cd uno-repo\build
  • convert-sourcetree-to-winui.cmd

You'll need to ensure that the crosstargeting_override.props file is not defining UnoTargetFrameworkOverride otherwise the UWPSyncGenerator will generate an invalid API set.