C#设计模式之行为型模式的示例分析-创新互联
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这里列举行为型模式·到此23种就列完了···这里是看着菜鸟教程来实现··，他里边列了25种，其中过滤器模式和空对象模式应该不属于所谓的23种模式
责任链模式：为请求创建一个接收者对象的链，对请求的发送者和接收者进行解耦，大部分用于web中吧。。
Task中的continuewith和微软的tpl数据流应该是类似这种模式的实现吧
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//责任链模式
namespace ExercisePrj.Dsignmode
{
public abstract class AbstractLogger
{
public static int INFO = 1;
public static int DEBUG = 2;
public static int ERROR = 3;
protected int level;
//责任链中的下一个对象
protected AbstractLogger nextLogger;
public void SetNextLogger(AbstractLogger next)
{
nextLogger = next;
}
public void LogMessage(int level,string message)
{
if(this.level<=level)
{
Write(message);
}
if(nextLogger!=null)
{
nextLogger.LogMessage(level, message);
}
}
protected abstract void Write(string message);
}
public class ConsoleLogger : AbstractLogger
{
public ConsoleLogger(int level)
{
this.level = level;
}
protected override void Write(string message)
{
Console.WriteLine("Standard Console::Logger: " + message);
}
}
public class ErrorLogger : AbstractLogger
{
public ErrorLogger(int level)
{
this.level = level;
}
protected override void Write(String message)
{
Console.WriteLine("Error Console::Logger: " + message);
}
}
public class FileLogger : AbstractLogger
{
public FileLogger(int level)
{
this.level = level;
}
protected override void Write(String message)
{
Console.WriteLine("File::Logger: " + message);
}
}
}命令模式（Command Pattern）:请求以命令的形式执行，CAD的的命令应该就是以这种方式执行的·二次开发的时候通过特性标识和继承他的接口来添加命令，非常方便
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//命令模式
namespace ExercisePrj.Dsignmode
{
public interface IOrder
{
void Execute();
}
public class Stock
{
private string name = "ABC";
private int quantity = 10;
public void Buy()
{
Console.WriteLine("Stock name:{0},quantity:{1},bought",name,quantity);
}
public void Sell()
{
Console.WriteLine("Stock name:{0},quantity:{1}sold", name, quantity);
}
}
//请求类
public class BuyStock : IOrder
{
private Stock abcStock;
public BuyStock(Stock abcStock)
{
this.abcStock = abcStock;
}
public void Execute()
{
abcStock.Buy();
}
}
//继承接口的实体
public class SellStock : IOrder
{
private Stock abcStock;
public SellStock(Stock abcStock)
{
this.abcStock = abcStock;
}
public void Execute()
{
abcStock.Sell();
}
}
//命令调用类
public class Broker
{
private List orderList = new List();
public void takeOrder(IOrder order)
{
orderList.Add(order);
}
public void placeOrders()
{
foreach (IOrder order in orderList)
{
order.Execute();
}
orderList.Clear();
}
}
} 解释器模式：就是实现一种表达式接口，C#的各种表达式就是这种实现吧··这玩意跟富文本编辑器一样是个大坑吧··，做好了确实很好使，一不小心就得跪
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//解释器模式
namespace ExercisePrj.Dsignmode
{
public interface Expression
{
bool Interpret(string context);
}
public class TerminalExpression : Expression
{
private string data;
public TerminalExpression(string data)
{
this.data = data;
}
public bool Interpret(string context)
{
if (context.Contains(data))
{
return true;
}
return false;
}
}
public class OrExpression : Expression
{
private Expression expr1 = null;
private Expression expr2 = null;
public OrExpression(Expression expr1, Expression expr2)
{
this.expr1 = expr1;
this.expr2 = expr2;
}
public bool Interpret(String context)
{
return expr1.Interpret(context) || expr2.Interpret(context);
}
}
public class AndExpression : Expression
{
private Expression expr1 = null;
private Expression expr2 = null;
public AndExpression(Expression expr1, Expression expr2)
{
this.expr1 = expr1;
this.expr2 = expr2;
}
public bool Interpret(String context)
{
return expr1.Interpret(context) && expr2.Interpret(context);
}
}
}迭代器模式（Iterator Pattern）：.NET自带接口···，直接实现就行了··注意又泛型接口和非泛型接口··非泛型接口迭代对象返回的是object，泛型接口返回的直接就是对象了，还有通过yield的简化写法不用额外去实现IEnumerator接口
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ExercisePrj.Dsignmode
{
public class IteratorEx : IEnumerable //
{
public string Name;
private List list = new List();
//public IEnumerator GetEnumerator()
//{
// foreach (var l in list)
// {
// yield return l;
// }
//}
public void SetList(List data)
{
list = data;
}
IEnumerator IEnumerable.GetEnumerator()
{
foreach (var l in list)
{
yield return l;
}
//return new IteratorExEnum(list.ToArray());
}
}
public class IteratorExEnum : IEnumerator
{
private IteratorEx[] list;
private int position = -1;
public IteratorExEnum(IteratorEx[] data)
{
list = data;
}
public object Current
{
get
{
try
{
return list[position];
}
catch (IndexOutOfRangeException)
{
throw new InvalidOperationException();
}
}
}
public bool MoveNext()
{
position++;
return position < list.Length;
}
public void Reset()
{
position = -1;
}
}
} 中介者模式（Mediator Pattern）：用一个中介对象封装一些对象的交互，中介者使对象不用显式的互相引用，MVC和mvp 的c和p都是类似这玩意的实现吧
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ExercisePrj.Dsignmode
{
//中介类
public class ChatRoom
{
public static void ShowMessage(User user, string msg)
{
Console.WriteLine(new DateTime().ToString()+"["+ user.Name + "] : " + msg);
}
}
public class User
{
public string Name { get; set; }
public User(string name)
{
Name = name;
}
public void SendMessage(String message)
{
ChatRoom.ShowMessage(this, message);
}
}
}备忘录模式（Memento Pattern）：在不破坏封装的前提下，捕获一个对象的内部状态，并在对象之外保存，
大部分支持回退的操作场景下应该都是这种模式··之前做的软件中有画图的操作···支持后退，实现方式非常简单粗暴··，直接吧图层的画图对象克隆一份保存··只支持5还是10步，讲道理这么实现确实有点那啥了···
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ExercisePrj.Dsignmode
{
public class Memento
{
public string State { get; }
public Memento(string state)
{
State = state;
}
}
public class Originator
{
public string State { get; set; }
public Memento SaveStateToMemento()
{
return new Memento(State);
}
public void GetStateFromMemento(Memento Memento)
{
State = Memento.State;
}
}
public class CareTaker
{
private List mementoList = new List();
public void Add(Memento state)
{
mementoList.Add(state);
}
public Memento Get(int index)
{
return mementoList[index];
}
}
} 观察者模式（Observer Pattern）：.net自带的有接口提供来实现观察者模式···这里照着msdn来实现一遍，自带的接口里边还实现了资源的释放··，之前并发编程里边的rx也是这个模式的具体实现·
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//观察者模式
namespace ExercisePrj.Dsignmode
{
public class Subject: IObservable
{
public int State {get; set;}
public Subject(int state)
{
State = state;
}
private List> observers = new List>();
public IDisposable Subscribe(IObserver observer)
{
if (!observers.Contains(observer))
observers.Add(observer);
return new Unsubscriber(observers, observer);
}
private class Unsubscriber : IDisposable
{
private List> _observers;
private IObserver _observer;
public Unsubscriber(List> observers, IObserver observer)
{
this._observers = observers;
this._observer = observer;
}
public void Dispose()
{
if (_observer != null && _observers.Contains(_observer))
_observers.Remove(_observer);
}
}
public void TrackLocation(Subject ob)
{
Console.WriteLine("start");
foreach (var observer in observers)
{
if (ob==null)
observer.OnError(new Exception("unknowExeption"));
else
observer.OnNext(ob);
}
}
public void EndTransmission()
{
foreach (var observer in observers.ToArray())
if (observers.Contains(observer))
observer.OnCompleted();
observers.Clear();
}
}
public class BinaryObserver : IObserver
{
public void OnCompleted()
{
Console.WriteLine("complete");
}
public void OnError(Exception error)
{
Console.WriteLine(error.Message);
}
public void OnNext(Subject value)
{
Console.WriteLine("Binary String: " + Convert.ToString(value.State, 2));
}
}
public class OctalObserver : IObserver
{
public void OnCompleted()
{
Console.WriteLine("complete");
}
public void OnError(Exception error)
{
Console.WriteLine(error.Message);
}
public void OnNext(Subject value)
{
Console.WriteLine("Octal String: " + Convert.ToString(value.State, 8));
}
}
public class HexaObserver : IObserver
{
public void OnCompleted()
{
Console.WriteLine("complete");
}
public void OnError(Exception error)
{
Console.WriteLine(error.Message);
}
public void OnNext(Subject value)
{
Console.WriteLine("Hex String: " + Convert.ToString(value.State,16));
}
}
} 状态模式（State Pattern）：当对象内部状态发生改变时，行为也跟着改变
这个模式是为了解决类里边的大量if和swicth语句，讲道理例子写的有点怪···主体是context
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ExercisePrj.Dsignmode
{
public class Context
{
public State State { get; set; }
public Context()
{
State = null;
}
}
public interface State
{
void DoAction(Context context);
}
public class StartState : State
{
public void DoAction(Context context)
{
Console.WriteLine("Player is in start state");
context.State = this;
}
public override string ToString()
{
return "Start State";
}
}
public class StopState : State
{
public void DoAction(Context context)
{
Console.WriteLine("Player is in stop state");
context.State = this;
}
public override string ToString()
{
return "Stop State";
}
}
}空对象模式（Null Object Pattern）：就是吧对空值的判断定义一个啥也不做的实体对象出来··C#的Nullable就是这个的实现···这玩意不在23种设计模式里边···
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ExercisePrj.Dsignmode
{
public abstract class AbstractCustomer
{
public abstract bool IsNull();
public abstract string Name { get; }
}
public class RealCustomer : AbstractCustomer
{
public override string Name { get; }
public RealCustomer(string name)
{
Name = name;
}
public override bool IsNull()
{
return false;
}
}
public class NullCustomer : AbstractCustomer
{
public override string Name { get { return "Not Available in Customer Database"; } }
public override bool IsNull()
{
return true;
}
}
public class CustomerFactory
{
public static string[] names = {"Rob", "Joe", "Julie"};
public static AbstractCustomer getCustomer(string name)
{
if(names.Contains(name))
{
return new RealCustomer(name);
}
return new NullCustomer();
}
}
}策略模式（Strategy Pattern）：定义一系列算法，封装成类，可以相互替换，通过构造不同的类，执行不同的操作。这样做方便调用，添加新的算法也方便，
最后加了自己之前对这个模式的奇葩写法
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
namespace ExercisePrj.Dsignmode
{
public interface IStrategy
{
int DoOperation(int num1, int num2);
}
public class OperationAdd : IStrategy
{
public int DoOperation(int num1, int num2)
{
return num1 + num2;
}
}
public class OperationSubstract : IStrategy
{
public int DoOperation(int num1, int num2)
{
return num1 - num2;
}
}
public class OperationMultiply : IStrategy
{
public int DoOperation(int num1, int num2)
{
return num1 * num2;
}
}
public class ContextEx
{
private IStrategy strategy;
public ContextEx(IStrategy strategy)
{
this.strategy = strategy;
}
public int ExecuteStrategy(int num1, int num2)
{
return strategy.DoOperation(num1, num2);
}
//奇葩的写法简单粗暴
private Dictionary> funcs = new Dictionary>();
public int ExecuteStrategy(string name, int num1, int num2)
{
if(funcs.Count==0)
{
//反射写法
var assembly = Assembly.GetExecutingAssembly();
var types = assembly.GetTypes();
foreach (var t in types)
{
if (t.GetInterface("IStrategy") != null)
{
var instance = assembly.CreateInstance(t.FullName) as IStrategy;
funcs.Add(t.Name, instance.DoOperation);
}
}
//直接添加
//funcs.Add("OperationAdd", new Func((n1, n2) => { return n1 + n2; }));
//funcs.Add("OperationSubstract", new Func((n1, n2) => { return n1 - n2; }));
//funcs.Add("OperationMultiply", new Func((n1, n2) => { return n1 * n2; }));
}
return funcs[name](num1, num2);
}
}
}
模板模式（Template Pattern）：.net的泛型就是这个模式的实现吧··照着模子写就行了
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ExercisePrj.Dsignmode
{
public abstract class Game
{
public abstract void Initialize();
public abstract void StartPlay();
public abstract void EndPlay();
//模板
public void play()
{
//初始化游戏
Initialize();
//开始游戏
StartPlay();
//结束游戏
EndPlay();
}
}
public class Cricket : Game
{
public override void EndPlay()
{
Console.WriteLine("Cricket Game Finished!");
}
public override void Initialize()
{
Console.WriteLine("Cricket Game Initialized! Start playing.");
}
public override void StartPlay()
{
Console.WriteLine("Cricket Game Started. Enjoy the game!");
}
}
}访问者模式（Visitor Pattern）：在被访问的类里边加一个对外提供接待访问的接口
把数据结构和对应的操作分开·添加操作很容易，但是如果结构变化多的化，改起来就麻烦了··
没研究没用过····
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ExercisePrj.Dsignmode
{
public interface IComputerPartVisitor
{
void Visit(Computer computer);
void Visit(Mouse mouse);
void Visit(Keyboard keyboard);
void Visit(Monitor monitor);
}
public interface IComputerPart
{
void Accept(IComputerPartVisitor computerPartVisitor);
}
public class Keyboard : IComputerPart
{
public void Accept(IComputerPartVisitor computerPartVisitor)
{
computerPartVisitor.Visit(this);
}
}
public class Monitor : IComputerPart
{
public void Accept(IComputerPartVisitor computerPartVisitor)
{
computerPartVisitor.Visit(this);
}
}
public class Mouse : IComputerPart
{
public void Accept(IComputerPartVisitor computerPartVisitor)
{
computerPartVisitor.Visit(this);
}
}
public class Computer : IComputerPart
{
IComputerPart [] parts;
public Computer()
{
parts = new IComputerPart[] { new Mouse(), new Keyboard(), new Monitor() };
}
public void Accept(IComputerPartVisitor computerPartVisitor)
{
for (int i = 0; i < parts.Length; i++)
{
parts[i].Accept(computerPartVisitor);
}
computerPartVisitor.Visit(this);
}
}
public class ComputerPartDisplayVisitor : IComputerPartVisitor
{
public void Visit(Computer computer)
{
Console.WriteLine("Displaying Computer.");
}
public void Visit(Mouse mouse)
{
Console.WriteLine("Displaying Mouse.");
}
public void Visit(Keyboard keyboard)
{
Console.WriteLine("Displaying Keyboard.");
}
public void Visit(Monitor monitor)
{
Console.WriteLine("Displaying Monitor.");
}
}
}感谢各位的阅读！关于“C#设计模式之行为型模式的示例分析”这篇文章就分享到这里了，希望以上内容可以对大家有一定的帮助，让大家可以学到更多知识，如果觉得文章不错，可以把它分享出去让更多的人看到吧！
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