Proposal: Add C++/WinRT support for x:Property

Author: evelynwu-msftCreated Sep 9, 2026Updated Sep 18, 2026
Labelsfeature proposalarea-XamlCompilerteam-Markupteam-Core

Title

Add C++/WinRT support for x:Property directive

Summary

ADO PR 1077233 added support via XamlCompiler code generation for the x:Property directive but only for C#, C++/CX, and VB; C++/WinRT support was deliberately left as follow-up work (which never happened). This support still exists today so we currently have a feature gap between C# and C++/WinRT.

Rationale

Language gaps are confusing for developers and should not exist without very good reason. We have two options for how we deal with this:

  1. Add the missing C++/WinRT support
  2. Remove the existing C# support

It's unclear how many C# users currently take advantage of this feature but it's unlikely to be many (if even nonzero) given that it is completely undocumented.

Scope

No response

Important Notes

No response

Open Questions

No response

Source: microsoft/microsoft-ui-xaml