设计模式之—简单工厂模式<Simple Factory Pattern >

简单工厂模式结构图：

简单工厂模式以简单的加减乘除运算为例：

运算符类（Operation）：

namespace CalcTest.Simple_Factory_patterns
{
    class Operation
    {
        private double numberA = 0;
        private double numberB = 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;
            return result;
        }
    }
}

加法类（Add）：继承于运算符类（Operation）

namespace CalcTest.Simple_Factory_patterns
{
    class Add :Operation
    {
        public override double GetResult()
        {
            return NumberA + NumberB;
        }
    }
}

减法类（Subtraction）：继承于运算符类（Operation）

namespace CalcTest.Simple_Factory_patterns
{
    class Subtraction : Operation
    {
        public override double GetResult()
        {
            return NumberA - NumberB;
        }
    }
}

乘法类（Multiplacation）：继承于运算符类（Operation）

namespace CalcTest.Simple_Factory_patterns
{
    class Multiplication : Operation
    {
        public override double GetResult()
        {
            return NumberA * NumberB;
        }
    }
}

除法类（Division）：继承于运算符类（Operation）

namespace CalcTest.Simple_Factory_patterns
{
    class Division : Operation
    {
        public override double GetResult()
        {
            if (NumberB == 0)
            {
                throw new Exception("除数不能为0");
            }
            return NumberA / NumberB;
        }
    }
}

运算符工厂类（OperationFactory）：实例合适的对象，通过多态返回父类的方式实现计算结果

namespace CalcTest.Simple_Factory_patterns
{
    class OperationFactory
    {
        public static Operation createOperation(string operate)
        {
            Operation oper = null;
            switch (operate)
            {
                case "+":
                    oper = new Add();
                    break;
                case "-":
                    oper = new Subtraction();
                    break;
                case "*":
                    oper = new Multiplication();
                    break;
                case "/":
                    oper = new Division();
                    break;
            }
            return oper;
        }
    }
}

测试类（Main）：

namespace CalcTest.Simple_Factory_patterns
{
    class TestMain
    {
        public static void Main(string[] args)
        {
            Operation oper = null;
            //先输入操作符利用简单工厂模式创建类
            Console.Write("请输入操作符：(+、-、*、/)");
            string operate = Console.ReadLine();
            oper = OperationFactory.createOperation(operate);

            Console.Write("请输入数字A：");
            oper.NumberA = Convert.ToDouble(Console.ReadLine());

            Console.Write("请输入数字B：");
            oper.NumberB = Convert.ToDouble(Console.ReadLine());
            double result = oper.GetResult();
            Console.WriteLine("结果为：" + result);
            Console.ReadLine();
        }
    }
}

 

简单工厂模式操作结束！