How do I create a platform-specific custom renderer within a Xamarin.Forms class library?
I'm creating a Xamarin Forms class library that allows me to expand a picker's list with a tap anywhere on the control. That means I need to open the picker's list programmatically within the control's Tapped event handler.
This is trivial in the Android and iOS picker implementations - just a call to the picker's .Focus() method. However, the .Focus() method of the UWP's picker doesn't respond the same way - mainly because UWP must also handle mouse events, not just touch events.
Conceptually no problem, though, since I should be able to create a custom renderer for UWP to set the combobox's .DropDown property within the Tapped even handler.
Except...I'm not sure how to create a platform-specific custom renderer within a class library, since - unlike a normal Xamarin.Forms project - there are no platform-specific projects in which to implement custom renderers. Unfortunately, I haven't been able to find information anywhere about how to do this.
