工厂模式+配置文件+反射 实现数据库访问程序

控制台代码：

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Text;
  4 using System.Reflection;             //反射命名空间
  5 using System.Configuration;
  6 
  7 namespace AbstractorFactory
  8 {
  9     class Program
 10     {
 11         static void Main(string[] args)
 12         {
 13             User user = new User();
 14             IUser iu = DataAccess.CreateUser();
 15             iu.Insert(user);
 16             iu.GetUser(1);
 17             //IFactory factory = new AccessFactory();
 18             //IUser iu = factory.CreateUser();
 19             //iu.Insert(user);
 20             //iu.GetUser(1);
 21             Console.ReadLine();
 22         }
 23     }
 24     interface IUser
 25     {
 26         void Insert(User user);
 27         User GetUser(int id);
 28     }
 29     class User
 30     {
 31         private int _id;
 32 
 33         public int Id
 34         {
 35             get { return _id; }
 36             set { _id = value; }
 37         }
 38         private string _name;
 39 
 40         public string Name
 41         {
 42             get { return _name; }
 43             set { _name = value; }
 44         }
 45     }
 46     class SqlserverUser:IUser
 47     {
 48         public void Insert(User user)
 49         {
 50             Console.WriteLine("在Sql server中给User表增加一条记录");
 51         }
 52         public User GetUser(int id)
 53         {
 54             Console.WriteLine("在Sql server中根据id得到User表中的一条记录");
 55             return null;
 56         }
 57     }
 58     class AccessUser : IUser
 59     {
 60         public void Insert(User user)
 61         {
 62             Console.WriteLine("在Access中给User表增加一条记录");
 63         }
 64         public User GetUser(int id)
 65         {
 66             Console.WriteLine("在Access中根据id得到User表中的一条记录");
 67             return null;
 68         }
 69     }
 70     #region 抽象工厂模式
 71     //interface IFactory
 72     //{
 73     //    IUser CreateUser();
 74     //}
 75     //class SqlServerFactory : IFactory
 76     //{
 77     //    public IUser CreateUser()
 78     //    {
 79     //        return new SqlserverUser();
 80     //    }
 81     //}
 82     //class AccessFactory : IFactory
 83     //{
 84     //    public IUser CreateUser()
 85     //    {
 86     //        return new AccessUser();
 87     //    }
 88     //}
 89     #endregion
 90     class DataAccess
 91     {
 92         private static readonly string db = ConfigurationSettings.AppSettings["db"];   
 93         private static readonly string assemblyName = "AbstractorFactory"; 
 94 
 95         public static IUser CreateUser()
 96         {
 97             //抽象工厂模式
 98             //IUse result=null;
 99             //switch (db)
100             //{
101             //    case "Sqlserver":
102             //        result = new SqlserverUser();
103             //        break;
104             //    case "AccessUser":
105             //        result = new AccessUser();
106             //        break;
107             //}
108             string className = assemblyName + "." + db + "User";
109             IUser result =(IUser)Assembly.Load(assemblyName).CreateInstance(className);   //利用反射技术实例化user.
110             return result;
111         }
112     }
113 }

app.config 文件

 <?xml version="1.0" encoding="utf-8" ?> 
2 <configuration>
3   <appSettings>
4     <add key="db" value="Sqlserver"/>
5   </appSettings>
6 </configuration>