DALFactory.cs

using System.Configuration;
using TASNET_Interface.IDAL;

namespace TASNET_Interface
{
    public class DALFactory : IDataAccess
    {
        private static string _dal = ConfigurationManager.AppSettings["Dal"];

        private static IDataAccess _dataAccess;
        public static IDataAccess DataAccess
        {
            get
            {
                if (_dataAccess == null) _dataAccess = GetDataAccess();
                return _dataAccess;
            }
        }
        
        private static IDataAccess GetDataAccess()
        {
            switch (_dal)
            {
                case "Production":
                    return null;

                case "Test":
                default:
                    return new TestDAL.TestDataAccess();
            }
        }

        #region IDataAccess Members

        public IEmployee Employee
        {
            get { return DataAccess.Employee; }
        }

        #endregion
    }
}