Microsoft Windows UI Library namespaces

The Windows UI Library (WinUI) is a native user experience (UX) framework for both Windows Desktop and Universal Windows Platform (UWP) applications.

There are two versions of WinUI that ship as NuGet packages: WinUI 2.x and WinUI 3. See the Windows UI Library overview for more details on both.

The namespaces and APIs documented here are valid for both versions.


See examples of WinUI features and controls in the XAML Controls Gallery sample app.

If you don't have the XAML Controls Gallery app installed, get the WinUI 2.x version from the Microsoft Store.

You can also view, clone, and build the XAML Controls Gallery source code from GitHub (switch to the WinUI 3 Preview branch for WinUI 3 Preview controls and features).

Microsoft.UI.Xaml Provides general framework APIs for the Windows UI Library (WinUI).
Microsoft.UI.Xaml.Automation.Peers Defines support types for the Microsoft UI Automation infrastructure.
Microsoft.UI.Xaml.Controls Provides UI controls and classes for creating custom controls.
Microsoft.UI.Xaml.Controls.Primitives Defines the components that comprise WinUI controls, or otherwise support the control composition model.
Microsoft.UI.Xaml.Core.Direct Provides a way for middleware authors to access low-level, high-performance XAML APIs and achieve better CPU and working set performance.
Microsoft.UI.Xaml.CustomAttributes Provides custom attributes (keyword-like descriptive declarations) that annotate programming elements such as types, fields, methods, and properties.
Microsoft.UI.Xaml.Media Provides brushes, basic media support, and graphics primitives.
Microsoft.UI.Xaml.XamlTypeInfo Provides support for the XAML schema.