C# Definition:

// Windows Ribbon Application interface
[ComImport]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[Guid("F4F0385D-6872-43a8-AD09-4C339CB3F5C5")]
public interface IUIFramework
{
     // Connects the framework and the application
     [PreserveSig]
     HRESULT Initialize(IntPtr frameWnd, IUIApplication application);

     // Releases all framework objects
     [PreserveSig]
     HRESULT Destroy();

     // Loads and instantiates the views and commands specified in markup
     [PreserveSig]
     HRESULT LoadUI(IntPtr instance, [MarshalAs(UnmanagedType.LPWStr)] string resourceName);

     // Retrieves a pointer to a view object
     [PreserveSig]
     HRESULT GetView(UInt32 viewId, Guid riid, [Out(), MarshalAs(UnmanagedType.Interface)] out object /* [out, iid_is(riid), annotation("__deref_out")] void** */ ppv);

     // Retrieves the current value of a property
     [PreserveSig]
     HRESULT GetUICommandProperty(UInt32 commandId, [In] ref PropertyKey key, out PropVariant value);

     // Immediately sets the value of a property
     [PreserveSig]
     HRESULT SetUICommandProperty(UInt32 commandId, [In] ref PropertyKey key, [In] ref PropVariant value);

     // Asks the framework to retrieve the new value of a property at the next update cycle
     [PreserveSig]
     HRESULT InvalidateUICommand(UInt32 commandId, UI_Invalidations flags, [In] ref PropertyKey key);

     // Flush all the pending UI command updates
     [PreserveSig]
     HRESULT FlushPendingInvalidations();

     // Asks the framework to switch to the list of modes specified and adjust visibility of controls accordingly
     [PreserveSig]
     HRESULT SetModes(Int32 iModes);
}

Notes:

None.