记录一本设计模式的书
常用设计模式有哪些？
策略设计模式
这里有一个 策略模式 C# 示例代码
using System;
using System.Collections.Generic;namespace RefactoringGuru.DesignPatterns.Strategy.Conceptual
{// The Context defines the interface of interest to clients.class Context{// The Context maintains a reference to one of the Strategy objects. The// Context does not know the concrete class of a strategy. It should// work with all strategies via the Strategy interface.private IStrategy _strategy;public Context(){ }// Usually, the Context accepts a strategy through the constructor, but// also provides a setter to change it at runtime.public Context(IStrategy strategy){this._strategy = strategy;}// Usually, the Context allows replacing a Strategy object at runtime.public void SetStrategy(IStrategy strategy){this._strategy = strategy;}// The Context delegates some work to the Strategy object instead of// implementing multiple versions of the algorithm on its own.public void DoSomeBusinessLogic(){Console.WriteLine("Context: Sorting data using the strategy (not sure how it'll do it)");var result = this._strategy.DoAlgorithm(new List<string> { "a", "b", "c", "d", "e" });string resultStr = string.Empty;foreach (var element in result as List<string>){resultStr += element + ",";}Console.WriteLine(resultStr);}}// The Strategy interface declares operations common to all supported// versions of some algorithm.//// The Context uses this interface to call the algorithm defined by Concrete// Strategies.public interface IStrategy{object DoAlgorithm(object data);}// Concrete Strategies implement the algorithm while following the base// Strategy interface. The interface makes them interchangeable in the// Context.class ConcreteStrategyA : IStrategy{public object DoAlgorithm(object data){var list = data as List<string>;list.Sort();return list;}}class ConcreteStrategyB : IStrategy{public object DoAlgorithm(object data){var list = data as List<string>;list.Sort();list.Reverse();return list;}}class Program{static void Main(string[] args){// The client code picks a concrete strategy and passes it to the// context. The client should be aware of the differences between// strategies in order to make the right choice.var context = new Context();Console.WriteLine("Client: Strategy is set to normal sorting.");context.SetStrategy(new ConcreteStrategyA());context.DoSomeBusinessLogic();Console.WriteLine();Console.WriteLine("Client: Strategy is set to reverse sorting.");context.SetStrategy(new ConcreteStrategyB());context.DoSomeBusinessLogic();}}
}Output.txt: 执行结果
Client: Strategy is set to normal sorting.
Context: Sorting data using the strategy (not sure how it'll do it)
a,b,c,d,eClient: Strategy is set to reverse sorting.
Context: Sorting data using the strategy (not sure how it'll do it)
e,d,c,b,a原文链接：C# 策略模式讲解和代码示例
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