Interface
    public interface ILog
    {
        ResultStatus ProcessAppLogging();
    }
Service

    public ResultStatus ProcessAppLogging(ILog objLog)
    {

        return objLog.ProcessAppLogging();
    }
Model

    public class UserLog
    {
        public string CustomerId { get; set; }
        public bool? IsMobile { get; set; }
        public int? DeviceId { get; set; }

 public ResultStatus ProcessAppLogging()
        {
            return UsersDownload(this);
        }
    }
    public class NonUserLog
    {
        public string DeviceId { get; set; }
        public bool? IsMobile { get; set; }
        public string AppType { get; set; }
 public ResultStatus ProcessAppLogging()
        {
            return NonUsersDownload(this);
        }
    }