WPF.Notifier (nuget): WPF.Notifier shows one or more toastnotification-windows.  Besides it's possible to show your own window with your viewmodel as a toastnotification.  (I)NotifierManager should be a Singleton, if you use it from different classes, because all notificationwindos are saved internally and removed after closing. You can use a DI Framework like Ninject and register INotifierManager as Singleton.  Then call ShowNotification/ShowCustomNotification .  If you want to show your own window, you have to handle the animations and closing by yourself.  Show your own Notification:  call ShowCustomNotification(yourViewModel)  in App.xaml:   <Application.Resources>         <DataTemplate DataType="{x:Type local:yourViewModel}">             <local:TestView />         </DataTemplate>     </Application.Resources>
Keywords: WPF|Notification|Toast|Toaster|Notifier