简单工厂模式(Simple Factory Pattern)

简单工厂模式定义一个类来负责创建其他类的实例，被创建的实例通常都具有共同的父类。因为在简单工厂模式中用于创建实例的方法是静态（static）方法，又叫做静态工厂方法（Static Factory Method）模式，简单工厂模式是属于创建型模式。

using System;
namespace ConsoleApplication
{
    //一般每个接口或类都写在单独的.cs文件中
    //本示例为了执行查看方便才写在一起
    public interface Database
    {
        void Delete();
        void Insert();
    }
    //Sqlserver的增删
    public class Sqlserver : Database
    {
        public void Delete()
        {
            Console.WriteLine("delete data from sqlserver");
        }
        public void Insert()
        {
            Console.WriteLine("insert data to sqlserver");
        }
    }
    //Mysql的增删
    public class Mysql : Database
    {
        public void Delete()
        {
            Console.WriteLine("delete data from Mysql");
        }
        public void Insert()
        {
            Console.WriteLine("insert data to Mysql");
        }
    }
    public static class IFactory
    {
        //根据需求创建
        public static Database CreateDatabase(string dbType)
        {
            Database db = null;
            switch (dbType)
            {
                case "Sqlserver":
                    db = new Sqlserver();
                    break;
                case "Mysql":
                    db = new Mysql();
                    break;
                default:
                    break;
            }
            return db;
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Database db1 = IFactory.CreateDatabase("Sqlserver");
            db1.Delete();
            db1.Insert();
            Database db2 = IFactory.CreateDatabase("Mysql");
            db2.Delete();
            db2.Insert();
            Console.ReadKey();
            Console.ReadKey();
        }
    }
}