Builder模式经典模式

  public class Vehicle
    {
        public IEnumerable<string> Wheels { get; set; }
        public IEnumerable<string> Lights { get; set; }
    }

    /// <summary>
    /// abstract builder
    /// </summary>
    public abstract class VehicleBuilderBase
    {
        public Vehicle Vehicle { get; protected set; }

        public virtual void Create()
        {
            Vehicle = new Vehicle();
        }

        public abstract void AddWheels();
        public abstract void AddLights();
    }

 /// <summary>
    /// concrete builder
    /// </summary>
    public class CarBuilder : VehicleBuilderBase
    {
        #region VehicleBuilderBase Members

        public override void AddWheels()
        {
            Vehicle.Wheels = new string[] {"front", "front", "back", "back"};
        }

        public override void AddLights()
        {
            Vehicle.Lights = new string[] { "front", "front", "back", "back" };
        }

        #endregion
    }

    /// <summary>
    /// concrete builder
    /// </summary>
    public class BicycleBuilder : VehicleBuilderBase
    {
        #region VehicleBuilderBase Members

        public override void AddWheels()
        {
            Vehicle.Wheels = new string[] { "front", "back" };
        }

        public override void AddLights()
        {
            Vehicle.Lights = null;
        }

        #endregion
    }

调用

   [TestMethod]
        public void BuildUp()
        {
            var maker = new VehicleMaker();
            maker.Builder = new CarBuilder();
            maker.Construct();
            Assert.AreEqual<int>(4, maker.Vehicle.Wheels.Count());
            Assert.AreEqual<int>(4, maker.Vehicle.Lights.Count());
            maker.Builder = new BicycleBuilder();
            maker.Construct();
            Assert.AreEqual<int>(2, maker.Vehicle.Wheels.Count());
            Assert.IsNull(maker.Vehicle.Lights);
            
        }