Make WindowNotificationManager Xaml friendly

[workgroupengineering]

Is your feature request related to a problem? Please describe.

Allow using WindowNotificationManager in Xaml

Describe the solution you'd like

• Mark WindowNotificationManager as obsolete
• Create a new NotificationManager, it's basically the same except the Position and MaxItems properties become attached properties. When using <Usertcontrol NotificationManager.Position="Center" in Xaml, it is checked if TopLevel has NotificationManager otherwise it instantiates a new one.

[timunie]

In latest master we relaxed the WNM already to make usage in xaml easier. I don't know if we want to invest more into it as I think we should instead invest our time into:

• native notifications API for each platform
• FluentAvalonia like ContentControl / DialogHost solution
• with 2), the Notification Manager can be extended to make use of the DialogHost probably.

[maxkatz6]

Avalonia/samples/ControlCatalog/Pages/NotificationsPage.xaml

Line 25 in 0567a6d

<WindowNotificationManager x:Name="ControlNotifications" />

[workgroupengineering]

I miss it. Tnx