Combine data sources using Or().

CombineUsingOrViewModel

namespace DynamicData.Samplz.Examples
{
    public class CombineUsingOrViewModel
    {
        public CombineUsingOrViewModel()
        {
            //maintain databaseDevices + databaseDevices anytime
            var databaseDevices = new SourceCache<IDevice,int>(device => device.Id);
            var localDevices = new SourceCache<IDevice, int>(device => device.Id);
    

            //combine both datasoures. 
            //Exclude updates if the current device is a DatabaseDevice and the previous is LocalDevice
            //[ensures LocalDevice gets precedent]
            //Alternatively, could use the same device object which has an extra Enum property for DeviceSource and adjust IgnoreUpdate lambda acordingly
            var combinedDevices = databaseDevices.Connect()
                .Or(localDevices.Connect())
                .IgnoreUpdateWhen((current, previous) => current is DatabaseDevice && previous is LocalDevice)
                .AsObservableCache();

            //Do normal dd stuff like binding, or expose combinedDevices as a new data source
        }
    }

    public interface IDevice
    {
        int Id { get; }
        string Name { get; }
    }

    public class DatabaseDevice: IDevice
    {
        public int Id { get; }
        public string Name { get; }
        
        public DatabaseDevice(int id, string name)
        {
            Id = id;
            Name = name;
        }
    }

    public class LocalDevice : IDevice
    {
        public int Id { get; }
        public string Name { get; }

        public LocalDevice(int id, string name)
        {
            Id = id;
            Name = name;
        }
    }


}