public abstract class Builder{public abstract void BuildDoor();public abstract void BuildWall();public abstract void BuildWindow();public abstract void BuildFloor();public abstract void BuildHouseCeiling();public abstract House GetHouse();}

        public void Constract(Builder builder){builder.BuildWall();builder.BuildHouseCeiling();builder.BuildDoor();builder.BuildWindow();builder.BuildFloor();}

    public class ChineseBuilder: Builder{private House ChineseHouse = new House();public override void BuildDoor(){Console.WriteLine("this Door 's style of Chinese");}public override void BuildWall(){Console.WriteLine("this Wall 's style of Chinese");}public override void BuildWindow(){Console.WriteLine("this Windows 's style of Chinese");}public override void BuildFloor(){Console.WriteLine("this Floor 's style of Chinese");}public override void BuildHouseCeiling(){Console.WriteLine("this Ceiling 's style of Chinese");}public override House GetHouse(){return ChineseHouse;}}

    public class RomanBuilder:Builder{private House RomanHouse = new House();public override void BuildDoor(){Console.WriteLine("this Door 's style of Roman");}public override void BuildWall(){Console.WriteLine("this Wall 's style of Roman");}public override void BuildWindow(){Console.WriteLine("this Windows 's style of Roman");}public override void BuildFloor(){Console.WriteLine("this Floor 's style of Roman");}public override void BuildHouseCeiling(){Console.WriteLine("this Ceiling 's style of Roman");}public override House GetHouse(){return RomanHouse;}}

House类

    public class House{public void Show(){Console.WriteLine("House");}}

    class Program{static void Main(string[] args){Director director = new Director();Builder instance;Console.WriteLine("Please Enter House No:");string no = Console.ReadLine();string houseType = ConfigurationSettings.AppSettings["No" + no];Assembly ass = Assembly.GetExecutingAssembly();Type type = ass.GetType(ass.GetName().Name + ".FactoryMethod." + houseType);object obj_builder = Activator.CreateInstance(type);instance = (Builder)obj_builder;director.Constract(instance);House house = instance.GetHouse();house.Show();Console.ReadLine();}}

<?xml version="1.0" encoding="utf-8"?>
<configuration><appSettings><add key="No1" value="RomanBuilder"></add><add key="No2" value="ChineseBuilder"></add></appSettings>
</configuration>

Builder模式 主要用于“分步骤构建一个复杂的对象”。在这其中“分步骤”是一个稳定的乘法，而复杂对象的各个部分则经常变化。

Builder模式主要在于应对“复杂对象各个部分”的频繁需求变动。其缺点在于难以应对“分步骤构建算法”的需求变动。

Abstract Factory模式解决“系列对象”的需求变化，Builder模式解决“对象部分”的需求变化。Builder械通常和Composite模式组合使用。