// 抽象产品接口
public interface IButton { void Render(); }
public interface ITextBox { void Display(); }
// 具体产品（Windows家族）
public class WindowsButton : IButton {
public void Render() => Console.WriteLine("Windows风格按钮");
}
public class WindowsTextBox : ITextBox {
public void Display() => Console.WriteLine("Windows风格文本框");
}
// 抽象工厂接口
public interface IUIFactory {
IButton CreateButton();
ITextBox CreateTextBox();
}
// 具体工厂实现
public class WindowsUIFactory : IUIFactory {
public IButton CreateButton() => new WindowsButton();
public ITextBox CreateTextBox() => new WindowsTextBox();
}
// 客户端调用
var factory = new WindowsUIFactory();
var button = factory.CreateButton();
button.Render(); // 输出：Windows风格按钮
（2）设计原则
开闭原则：通过扩展（新增工厂类）而非修改现有代码支持新功能。
依赖倒置原则：高层模块依赖抽象接口而非具体实现。
（3）实战案例
需求：支持不同品牌（Benz、BMW）生产引擎和轮胎组件。
csharp复制代码
// 抽象产品
public interface IEngine { void Start(); }
public interface ITyre { void Inflate(); }
// 具体产品（Benz家族）
public class BenzEngine : IEngine {
public void Start() => Console.WriteLine("Benz引擎启动");
}
public class BenzTyre : ITyre {
public void Inflate() => Console.WriteLine("Benz轮胎充气");
}
// 抽象工厂接口
public interface ICarFactory {
IEngine CreateEngine();
ITyre CreateTyre();
}
// 具体工厂（Benz工厂）
public class BenzFactory : ICarFactory {
public IEngine CreateEngine() => new BenzEngine();
public ITyre CreateTyre() => new BenzTyre();
}
// 客户端调用
ICarFactory factory = new BenzFactory();
var engine = factory.CreateEngine();
engine.Start(); // 输出：Benz引擎启动
// 1. 产品类：Computer
public class Computer {
public string CPU { get; set; }
public string Motherboard { get; set; }
public string RAM { get; set; }
public string Storage { get; set; }
public void DisplaySpecs() {
Console.WriteLine($"CPU: {CPU}\n主板: {Motherboard}\n内存: {RAM}\n存储: {Storage}");
}
}
// 2. 抽象建造者：IComputerBuilder
public interface IComputerBuilder {
void SetCPU(string cpu);
void SetMotherboard(string motherboard);
void SetRAM(string ram);
void SetStorage(string storage);
Computer GetComputer();
}
// 3. 具体建造者：GamingComputerBuilder
public class GamingComputerBuilder : IComputerBuilder {
private Computer _computer = new Computer();
public void SetCPU(string cpu) => _computer.CPU = cpu;
public void SetMotherboard(string motherboard) => _computer.Motherboard = motherboard;
public void SetRAM(string ram) => _computer.RAM = ram;
public void SetStorage(string storage) => _computer.Storage = storage;
public Computer GetComputer() => _computer;
}
// 4. 指挥者（可选）：ComputerDirector
public class ComputerDirector {
public Computer Build(IComputerBuilder builder) {
builder.SetCPU("Intel i9");
builder.SetMotherboard("Z690");
builder.SetRAM("32GB DDR5");
builder.SetStorage("1TB NVMe SSD");
return builder.GetComputer();
}
}
// 客户端调用
var builder = new GamingComputerBuilder();
var director = new ComputerDirector();
var gamingPC = director.Build(builder);
gamingPC.DisplaySpecs();
（2）绘制人物
应用场景： 图形界面中分步绘制复杂图形
csharp复制代码
// 1. 抽象建造者：PersonBuilder
public abstract class PersonBuilder {
protected Graphics Graphics { get; }
protected Pen Pen { get; }
public PersonBuilder(Graphics g, Pen p) {
Graphics = g;
Pen = p;
}
public abstract void BuildHead();
public abstract void BuildBody();
public abstract void BuildArms();
public abstract void BuildLegs();
}
// 2. 具体建造者：PersonThinBuilder
public class PersonThinBuilder : PersonBuilder {
public PersonThinBuilder(Graphics g, Pen p) : base(g, p) {}
public override void BuildHead() => Graphics.DrawEllipse(Pen, 50, 20, 30, 30);
public override void BuildBody() => Graphics.DrawRectangle(Pen, 60, 50, 10, 50);
public override void BuildArms() => Graphics.DrawLine(Pen, 60, 50, 40, 100);
public override void BuildLegs() => Graphics.DrawLine(Pen, 60, 100, 50, 150);
}
// 3. 客户端调用（Windows窗体示例）
var bitmap = new Bitmap(200, 200);
using (var g = Graphics.FromImage(bitmap)) {
var pen = new Pen(Color.Black);
var builder = new PersonThinBuilder(g, pen);
builder.BuildHead();
builder.BuildBody();
builder.BuildArms();
builder.BuildLegs();
}
pictureBox.Image = bitmap;
（3）链式调用
通过链式方法调用简化客户端代码，常见于配置类库（如HTTP请求构建）
csharp复制代码
public class Car {
public string Engine { get; set; }
public int Wheels { get; set; }
public string Color { get; set; }
}
public class CarBuilder {
private Car _car = new Car();
public CarBuilder SetEngine(string engine) { _car.Engine = engine; return this; }
public CarBuilder SetWheels(int wheels) { _car.Wheels = wheels; return this; }
public CarBuilder SetColor(string color) { _car.Color = color; return this; }
public Car Build() => _car;
}
// 客户端调用
var car = new CarBuilder()
.SetEngine("V8")
.SetWheels(4)
.SetColor("Red")
.Build();
3、进阶技巧
（1）省略Director
直接通过客户端调用Builder方法（适用于简单流程）。
（2）参数校验
在Build()方法中加入校验逻辑，确保对象完整性。
csharp复制代码
public Car Build() {
if (_car.Wheels < 4) throw new ArgumentException("车轮不足");
return _car;
}
（3）不可变对象
通过私有构造函数 + Builder实现（线程安全）。
csharp复制代码
public class ImmutableCar {
public string Engine { get; }
private ImmutableCar(CarBuilder builder) {
Engine = builder.Engine;
}
public class CarBuilder {
public string Engine { get; set; }
public ImmutableCar Build() => new ImmutableCar(this);
}
}
// 抽象产品接口：ILog
public interface ILog
{
void Write(string message);
}
// 具体产品：文件日志
public class FileLog : ILog
{
public void Write(string message)
{
Console.WriteLine($"FileLog: {message}");
}
}
// 具体产品：事件日志
public class EventLog : ILog
{
public void Write(string message)
{
Console.WriteLine($"EventLog: {message}");
}
}
（2）定义抽象与具体工厂
csharp复制代码
// 抽象工厂接口：ILogFactory
public interface ILogFactory
{
ILog CreateLog();
}
// 具体工厂：文件日志工厂
public class FileLogFactory : ILogFactory
{
public ILog CreateLog()
{
return new FileLog();
}
}
// 具体工厂：事件日志工厂
public class EventLogFactory : ILogFactory
{
public ILog CreateLog()
{
return new EventLog();
}
}
（3）客户端调用
csharp复制代码
class Program
{
static void Main(string[] args)
{
// 通过具体工厂创建产品
ILogFactory factory = new FileLogFactory();
ILog logger = factory.CreateLog();
logger.Write("Test message"); // 输出：FileLog: Test message
// 切换工厂类型
factory = new EventLogFactory();
logger = factory.CreateLog();
logger.Write("Test message"); // 输出：EventLog: Test message
}
}
（4）模式扩展：新增类型
若需支持数据库日志，只需添加新的产品类和工厂类，而无需修改原有代码：
csharp复制代码
// 新增具体产品：数据库日志
public class DatabaseLog : ILog
{
public void Write(string message)
{
Console.WriteLine($"DatabaseLog: {message}");
}
}
// 新增具体工厂：数据库日志工厂
public class DatabaseLogFactory : ILogFactory
{
public ILog CreateLog()
{
return new DatabaseLog();
}
}
3、进阶技巧
（1）结合依赖注入
通过IoC容器管理工厂和产品的生命周期。
（2）泛型工厂
利用C#泛型简化工厂类的实现。
csharp复制代码
public interface IGenericFactory<T> where T : ILog, new()
{
T Create() => new T();
}