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  • 【设计模式】简单工厂模式学习

    任何类的设计都要遵循耦合性低,避免重复。

    设计模式的目的主要有3易。让项目易维护,易扩展,易复用。

    易维护: 修改某个功能,只要修改最少的部分,比如某个类的方法。

    易扩展: 项目本来有加减乘除功能,现在要扩展 根号,取余功能。  要尽量的少改代码。

    易复用: 要让设计的方法不管在 控制台应用程序,web应用程序 还是 Winform程序都能使用。

    简单工厂模式:解决了对象的创建问题

    Operator.cs 定义了几个类,实现了加减功能。    其中通过OpeartorFactor 根据操作符来实例相应的对象。

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
     
    namespace 简单工厂模式
    {
        class Operation
        {
            private double _numberA = 0.0;
            private double _numberB = 0.0;
     
            public double NumberA
            {
                get { return _numberA; }
                set { _numberA = value; }
            }
     
            public double NumberB
            {
                get { return _numberB; }
                set { _numberB = value; }
            }
     
     
            public virtual double getResult()
            {
                double result = 0.0;
                return result;
     
            }
     
     
        }
     
        class OpeartionAdd : Operation
        {
            public override double getResult()
            {
                double result = 0.0;
                result = NumberA + NumberB;
                return result;
            }
     
        }
     
     
        class OpeartionDel : Operation
        {
            public override double getResult()
            {
                double result = 0.0;
                result = NumberA - NumberB;
                return result;
     
            }
     
        }
     
        class OperationFactory
        {
            public static Operation createOpeartion(string operate)
            {
                Operation oper = null;
                switch (operate)
                {
                    case "+":
                        oper = new OpeartionAdd();
                        break;
                    case "-":
                        oper = new OpeartionDel();
                        break;
     
     
                }
                return oper;
     
     
     
            }
     
     
        }
    }
     

    现在想加入 乘除功能,那怎么办呢?

    只要 先添加 2个类,并重写getResult()方法,然后再 工厂类中 加入  符号的判断

    class  OpeartionMul:Operation    

    class  OpeartionDiv:Operation 

    case "*":
              oper = new OpeartionMul();
              break;
     
     
     
    修改后的文件
     
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
     
    namespace 简单工厂模式
    {
        class Operation
        {
            private double _numberA = 0.0;
            private double _numberB = 0.0;
     
            public double NumberA
            {
                get { return _numberA; }
                set { _numberA = value; }
            }
     
            public double NumberB
            {
                get { return _numberB; }
                set { _numberB = value; }
            }
     
     
            public virtual double getResult()
            {
                double result = 0.0;
                return result;
     
            }
     
     
        }
     
        class OpeartionAdd : Operation
        {
            public override double getResult()
            {
                double result = 0.0;
                result = NumberA + NumberB;
                return result;
            }
     
        }
     
     
        class OpeartionDel : Operation
        {
            public override double getResult()
            {
                double result = 0.0;
                result = NumberA - NumberB;
                return result;
     
            }
     
        }
     
        class OpeartionMul : Operation
        {
            public override double getResult()
            {
                double result = 0.0;
                result = NumberA * NumberB;
                return result;
     
            }
     
        }
     
        class OpeartionDiv : Operation
        {
            public override double getResult()
            {
                double result = 0.0;
                result = NumberA / NumberB;
                return result;
     
            }
     
        }
        class OperationFactory
        {
            public static Operation createOpeartion(string operate)
            {
                Operation oper = null;
                switch (operate)
                {
                    case "+":
                        oper = new OpeartionAdd();
                        break;
                    case "-":
                        oper = new OpeartionDel();
                        break;
                    case "*":
                        oper = new OpeartionMul();
                        break;
                    case "/":
                        oper = new OpeartionDiv();
                        break;
     
                }
                return oper;
     
     
     
            }
     
     
        }
    }
     
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  • 原文地址:https://www.cnblogs.com/StudyLife/p/2396689.html
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