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。

 

var director = new Director();
var sanxingBuilder = new SanxingBuilder();
director.Build(sanxingBuilder);
var sanxingComputer = sanxingBuilder.GetComputer();
Console.WriteLine(sanxingComputer);

var dellBuilder = new DellBuilder();
director.Build(dellBuilder);
var dellComputer = dellBuilder.GetComputer();
Console.WriteLine(dellComputer);

//1、定义要构建的对象 电脑
public class Computer
{
    public string Cup { get; set; } = string.Empty;
    public string Memory { get; set; } = string.Empty;
    public string Mainbord { get; set; } = string.Empty;
    public string Screen { get; set; } = string.Empty;

    public override string ToString()
    {
        return $"Cup:{Cup},Memory:{Memory},Mainbord:{Mainbord},Screen:{Screen}";
    }
}

//2、定义一个抽象构建器
public abstract class Builder
{
    public abstract Builder BuildCpu();//返回类型是自己（Builder），这样就支持链式调用
    public abstract Builder BuildMemory();
    public abstract Builder BuildMainbord();
    public abstract Builder BuildScreen();

    public abstract Computer GetComputer();
}

//3、实现构建起 三星
public class SanxingBuilder : Builder
{
    private readonly Computer _computer = new Computer();

    public override Builder BuildCpu()
    {
        _computer.Cup = "三星 CUP";
        Console.WriteLine(_computer.Cup);
        return this;
    }

    public override Builder BuildMainbord()
    {
        _computer.Mainbord = "三星 CUP";
        Console.WriteLine(_computer.Mainbord);
        return this;
    }

    public override Builder BuildMemory()
    {
        _computer.Memory = "三星 Memory";
        Console.WriteLine(_computer.Memory);
        return this;
    }

    public override Builder BuildScreen()
    {
        _computer.Screen = "三星 Screen";
        Console.WriteLine(_computer.Screen);
        return this;
    }

    public override Computer GetComputer()
    {
        return _computer;
    }
}

//3实现 构建者 dell
public class DellBuilder : Builder
{
    private readonly Computer _computer = new Computer();
    public override Builder BuildCpu()
    {
        _computer.Cup = "戴尔 CUP";
        Console.WriteLine(_computer.Cup);
        return this;
    }

    public override Builder BuildMainbord()
    {
        _computer.Mainbord = "戴尔 Mainbord";
        Console.WriteLine(_computer.Mainbord);
        return this;
    }

    public override Builder BuildMemory()
    {
        _computer.Memory = "戴尔 Memory";
        Console.WriteLine(_computer.Memory);
        return this;
    }

    public override Builder BuildScreen()
    {
        _computer.Screen = "戴尔 Screen";
        Console.WriteLine(_computer.Screen);
        return this;
    }

    public override Computer GetComputer()
    {
        return _computer;
    }
}

//4、导演角色、编排构建顺序
public class Director
{
    public void Build(Builder builder)
    {
        builder
            .BuildCpu()
            .BuildMainbord()
            .BuildMemory()
            .BuildScreen();
    }
}