This library is obsolete and doesn't target newer versions of Android & iOS.
I strongly recommend to use Xamarin.Essentials to read contacts.
Read Contacts Data on iOS and Android
Easy usage in Portable Project:
var contacts = await Plugin.ContactService.CrossContactService.Current.GetContactListAsync();
You can generate ObservableCollection like that:
var contacts = await Plugin.ContactService.CrossContactService.Current.GetContactListAsync();
ObservableCollection<Contact> = new ObservableCollection<Contact>(contacts);
You can use filter like that:
var contacts = await Plugin.ContactService.CrossContactService.Current.GetContactListAsync(x=>x.Emails.Count > 0);
DO NOT FORGET ADD THIS PERMISSIONS:
READ_CONTACTS
If you don't have mac connection you should Right Click the Info.plist and Open With XML editor. Add this key into
<key>NSContactsUsageDescription</key>
<string>We need contact permission to do ...</string>