There might be a problem in your constructor. Your assigning the backing field _details
to the public property for that backing field KabaDevices
. Not 100% sure whether this is the reason for the exception, but everything else should work fine, as far as I can tell. Try this:
public KabaDeviceListViewModel()
{
var details = new ObservableCollection<KabaDeviceDetailViewModel>();
KabaDevice kd1 = new KabaDevice("localhost A", "127.0.0.1", true);
KabaDeviceDetailViewModel dvm = new KabaDeviceDetailViewModel(kd1);
details.Add(dvm);
KabaDevice kd2 = new KabaDevice("localhost B", "127.0.0.1", true);
KabaDeviceDetailViewModel dvm2 = new KabaDeviceDetailViewModel(kd2);
details.Add(dvm2);
this.KabaDevices = details;
}