Xamarin architechture for sharing events between android platform and ViewModel - mvvm

Question

I have an application running on a Janam XT2 handheld computer.
I have the scanner library piece for the Andriod project working fine. I wanted to be able to pass the scanned event to a viewmodel. I can't seem to figure out what I am doing wrong.
The setup is as follows
Using Prism, VS 2017, MVVM.
Shared Project containing barcode specific classes. Shared with Android project and an MVVM Module for my data.
I have a separate MVVM Module for my current UI.
In the android MainActivity I have a reference to the App instance which has a property of EventAggregator. When the scanner's Received event is fired in the Android application (MainActivity) I am Publishing a ScannerEvent.
This is working the way I think it should, but trying to Subscribe to that event in a ViewModel results in nothing.
Anyone have any ideas?
EDIT: in response to request in comment by Nkosi.
public ListViewBaseModel(IEventAggregator eventAggregator)
{
_eventAggregator = eventAggregator;
Warehouses = new ObservableCollectionFast<WarehouseListItem>(Client.GetAsync(new WarehouseListQuery() { CompanyID = "SPF", UseBins = 1 }).Result.Results);
_eventAggregator.GetEvent<BarcodeScannerEvent<ScanResults>>().Subscribe(BarcodeScanned);
}
public virtual void BarcodeScanned(ScanResults results)
{
}

Answer 1

If you create your event in a Shared Project, it will create a distinct type for each project referencing that (that's the nature of shared projects, they are like linked source files and will be added to the referencing assembly upon compilation).
This way, you create an event for the publisher and another event for the subscriber (even though they have the same name and look identical). Because the subscriber subscribes to a different event than the publisher publishes, the subscriber will not receive his event.
To resolve this, scrap the shared project and use a class library.