设计模式之[构建者模式(Builder)]-C#

说明：构建一个大对象时，可以分解成一个部分一个部分的构建，比如一台电脑由CUP、内存、主板、屏幕等，这些配件本身就是一个复杂的制造过程，一个一个构建后然后才组装成一台新的电脑。

步骤

1、定义要构建的对象——电脑

2、定义一个抽象的构建器，内部的每个抽象方法构建一个配件并返回构建器本身，目的是为了链式调用

3、构建器具体实现，如：三星构建器、戴尔构建器，

4、构建复杂对象是需要有顺序的，比如有些配件必须先构建，这时需要一个导演来指挥整个构建顺序

5、客户端使用构建器。创建一个导演实例和一个具体构建器实例如三星，然后把构建实例对象丢给导演去构建出电脑。

 

  1 var director = new Director();
  2 var sanxingBuilder = new SanxingBuilder();
  3 director.Build(sanxingBuilder);
  4 var sanxingComputer = sanxingBuilder.GetComputer();
  5 Console.WriteLine(sanxingComputer);
  6
  7 var dellBuilder = new DellBuilder();
  8 director.Build(dellBuilder);
  9 var dellComputer = dellBuilder.GetComputer();
 10 Console.WriteLine(dellComputer);
 11
 12 //1、定义要构建的对象 电脑
 13 public class Computer
 14 {
 15     public string Cup { get; set; } = string.Empty;
 16     public string Memory { get; set; } = string.Empty;
 17     public string Mainbord { get; set; } = string.Empty;
 18     public string Screen { get; set; } = string.Empty;
 19
 20     public override string ToString()
 21     {
 22         return $"Cup:{Cup},Memory:{Memory},Mainbord:{Mainbord},Screen:{Screen}";
 23     }
 24 }
 25
 26 //2、定义一个抽象构建器
 27 public abstract class Builder
 28 {
 29     public abstract Builder BuildCpu();//返回类型是自己（Builder），这样就支持链式调用
 30     public abstract Builder BuildMemory();
 31     public abstract Builder BuildMainbord();
 32     public abstract Builder BuildScreen();
 33
 34     public abstract Computer GetComputer();
 35 }
 36
 37 //3、实现构建起 三星
 38 public class SanxingBuilder : Builder
 39 {
 40     private readonly Computer _computer = new Computer();
 41
 42     public override Builder BuildCpu()
 43     {
 44         _computer.Cup = "三星 CUP";
 45         Console.WriteLine(_computer.Cup);
 46         return this;
 47     }
 48
 49     public override Builder BuildMainbord()
 50     {
 51         _computer.Mainbord = "三星 CUP";
 52         Console.WriteLine(_computer.Mainbord);
 53         return this;
 54     }
 55
 56     public override Builder BuildMemory()
 57     {
 58         _computer.Memory = "三星 Memory";
 59         Console.WriteLine(_computer.Memory);
 60         return this;
 61     }
 62
 63     public override Builder BuildScreen()
 64     {
 65         _computer.Screen = "三星 Screen";
 66         Console.WriteLine(_computer.Screen);
 67         return this;
 68     }
 69
 70     public override Computer GetComputer()
 71     {
 72         return _computer;
 73     }
 74 }
 75
 76 //3实现 构建者 dell
 77 public class DellBuilder : Builder
 78 {
 79     private readonly Computer _computer = new Computer();
 80     public override Builder BuildCpu()
 81     {
 82         _computer.Cup = "戴尔 CUP";
 83         Console.WriteLine(_computer.Cup);
 84         return this;
 85     }
 86
 87     public override Builder BuildMainbord()
 88     {
 89         _computer.Mainbord = "戴尔 Mainbord";
 90         Console.WriteLine(_computer.Mainbord);
 91         return this;
 92     }
 93
 94     public override Builder BuildMemory()
 95     {
 96         _computer.Memory = "戴尔 Memory";
 97         Console.WriteLine(_computer.Memory);
 98         return this;
 99     }
100
101     public override Builder BuildScreen()
102     {
103         _computer.Screen = "戴尔 Screen";
104         Console.WriteLine(_computer.Screen);
105         return this;
106     }
107
108     public override Computer GetComputer()
109     {
110         return _computer;
111     }
112 }
113
114 //4、导演角色、编排构建顺序
115 public class Director
116 {
117     public void Build(Builder builder)
118     {
119         builder
120             .BuildCpu()
121             .BuildMainbord()
122             .BuildMemory()
123             .BuildScreen();
124     }
125 }