I would like to create an application that responds to hook-able OS events. However, I need to be able to respond every time one of these events happen. In windows we would build a service that always runs -- I am pretty sure we cannot do this in iOS. I want the app to create the hook and present a configuration screen. But when the app is not running or is in the background, I still want the event processed. ( I found a library that looks like it can respond to the event I am concerned with.) Can I do this with Xamarin ? If so where can I start ?