To do barcode scanning with the RFD8500 scanner or read RFID tags through the RFD8500 you need to use the SDKs for RFID and scanning that the peripheral supports. Please see the product page here: RFD8500 1D/2D RFID Sled Support & Downloads | Zebra you will see both scanner and RFID SDKs but unfortunately these do not support Xamarin.
There is also another thread on this topic which may be of help, RFD8500 Development using Xamarin . The developer there did attempt to create a binding from the Java library to Xamarin but it did not succeed.
i can see there are separate sdks for rfid and barcode scanning for RFD8500. supposedly i create Xamarin IOS bindings for both the libraries, could i use both barcode and rfid scanning with 1 device at same time?
i mean, i have a requirement where i scan a barcode and based on the barcode, we do the rfid scan. in the past i have created an ios binding for rfid sdk library and create instance of srfidISdkApi interface and use rfidEstablishCommunicationSession() function to connect to the reader. suppose i have to use barcode before rfid scan would it mean creating instance of new object and connecting to barcode sdk session then disconnecting and then reconnecting to rfid session? or could it be done together?
I do not know for sure, I presume so but I recommend taking a look at what the team did in their "Scan Scan Write" application. It is available on the play store here: Zebra Scan Scan Write - Android Apps on Google Play and the source code can be downloaded for Android (Scan Scan Write Application for Android Support & Downloads | Zebra ) and iOS (Scan Scan Write Application for iOS Support & Downloads | Zebra ). That application should display best practice.