设计模式二(简单工厂模式)

public abstract class ConnectString
{
        //输出字符串  
        public abstract string GetConnectString();
}

    public class SqlConnectString : ConnectString
    {
        public override string GetConnectString()
        {
            return "SQL ConnectString";
            //throw new NotImplementedException();
        }
    }

    public class MySqlConnectString : ConnectString
    {
        public override string GetConnectString()
        {
            return "MySql ConnectString";
            //throw new NotImplementedException();
        }
    }

    public class SimpleFactory
    {
        /// <summary>
        /// 静态方法创建Product实例
        /// </summary>
        public static ConnectString CreatConnectString(string dbtype)
        {
            ConnectString connect = null;
            switch(dbtype)
            {
                case "MySql":
                    connect = new MySqlConnectString();
                    break;
                case "SqlServer":
                    connect = new SqlConnectString();
                    break;
            }
            return connect;
        }
    }

        static void Main(string[] args)
        {
            ConnectString connectString = SimpleFactory.CreatConnectString("MySql");
            Console.WriteLine(connectString.GetConnectString());

            ConnectString connectString2 = SimpleFactory.CreatConnectString("SqlServer");
            Console.WriteLine(connectString2.GetConnectString());

            Console.Read();
        }