C#反射，特性，数据库结合使用

来源：互联网发布：网眼软件官方下载编辑：程序博客网时间：2024/05/17 06:57

using System;using System.Reflection;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Configuration;using System.Data;using System.Data.SqlClient;namespace ConsoleApplication1{    //View    class Program    {        static void Main(string[] args)        {            StudentBll studentBll = new StudentBll();            Student model = studentBll.GetModelByID("3");            Console.WriteLine(model.ID + " " + model.Name + "    " + model.Age);            StudentMsgBll studentMsgBll = new StudentMsgBll();            StudentMsg modelMsg = studentMsgBll.GetModelByID("1");            Console.WriteLine(modelMsg.Id + " " + modelMsg.StuName + "    " + modelMsg.Age+"    "+modelMsg.Address);            Console.WriteLine("请按下键盘任意键退出！");            Console.ReadKey();        }    }    //model    [DBTableName("DBMyTest")]    public class Student    {        [DBField(true)]//调用DBField的有参构造函数，true说明是主键        public int ID { get; set; }        [DBField]//调用DBField的无参构造函数，默认不是主键        public string Name { get; set; }        [DBField]        public int Age { get; set; }    }    [DBTableName("DBMyTest")]    public class StudentMsg    {        [DBField(true)]        public int Id { get; set; }        [DBField]        public string StuName { get; set; }        [DBField]        public int Age { get; set; }        [DBField]        public string Address { get; set; }    }    //control    public class StudentBll : BaseBLL<Student>    {    }    public class StudentMsgBll : BaseBLL<StudentMsg>    {    }    //BaseBLL    public class BaseBLL<T> where T : class,new()//定义泛型类,T约束为引用类型和必须有一个无参构造函数    {        public virtual T GetModelByID(string ID)//虚方法，方便以后派生类用override        {            try            {                T model = null;                model = Activator.CreateInstance<T>();                PropertyInfo[] _PropertyInfo = model.GetType().GetProperties();                string TableName = model.GetType().Name;//得到类的名称，作为数据表名。                if (_PropertyInfo == null) return null;                else                {                    DBTableNameAttribute _DBTableNameAttribute = model.GetType().GetCustomAttribute<DBTableNameAttribute>();                    string _ConnectionString = _DBTableNameAttribute._DBConnection;//获取model类特性标志的数据库连接字符串                    using (SqlConnection con = new SqlConnection(_ConnectionString))                    {                        con.Open();                        string SelectCommand = "select * from "+TableName+" where ID=";                        foreach (PropertyInfo p in _PropertyInfo)                        {                            if (p.GetCustomAttribute<DBField>().GetIsID)//根据属性（property）的特性获取ID                            {                                SelectCommand += ID;                                break;                            }                        }                        SqlDataAdapter _SqlDataAdapter = new SqlDataAdapter(SelectCommand, con);                        DataSet _DataSet = new DataSet();                        _SqlDataAdapter.Fill(_DataSet);                        if (_DataSet.Tables[0].Rows.Count > 0)                        {                            DataRow _DataRow=_DataSet.Tables[0].Rows[0];                            foreach(PropertyInfo p in _PropertyInfo)                            {                                p.SetValue(model,_DataRow[p.Name]);                            }                            return model;//这里没什么好说的，用的是ADO.NET数据库访问                        }                        else return null;                    }                }            }            catch            {                return null;            }        }    }    //Attribute    [AttributeUsage(AttributeTargets.Class, AllowMultiple=false, Inherited=false)]    public class DBTableNameAttribute : Attribute    {        public string _DBTableName { get; set; }//数据表名        public string _DBConnection { get; set; }        public DBTableNameAttribute(string DBConnection)        {            _DBConnection = ConfigurationSettings.AppSettings.Get(DBConnection);//读取配置里面的数据库连接字符串        }    }    [AttributeUsage(AttributeTargets.Property,AllowMultiple=false,Inherited=false)]    public class DBField:Attribute    {        private bool _IsID = false;//默认不是主键        public DBField()        {        }        public DBField(bool IsID)         {            _IsID = IsID;        }        public bool GetIsID         {            get { return _IsID; }        }    }}

数据表结构如下：

USE [MyTest]GO/****** Object:  Table [dbo].[Student]    Script Date: 2016/4/25 15:17:12 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[Student]([ID] [int] IDENTITY(1,1) NOT NULL,[Name] [nvarchar](50) NULL,[Age] [int] NULL, CONSTRAINT [PK_Student] PRIMARY KEY CLUSTERED ([ID] ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]) ON [PRIMARY]GO

USE [MyTest]GO/****** Object:  Table [dbo].[StudentMsg]    Script Date: 2016/4/25 15:18:06 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[StudentMsg]([Id] [int] IDENTITY(1,1) NOT NULL,[StuName] [nvarchar](50) NOT NULL,[Age] [int] NULL,[Address] [nvarchar](200) NULL, CONSTRAINT [PK_StudentMsg] PRIMARY KEY CLUSTERED ([Id] ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]) ON [PRIMARY]GO

控制台app.config配置

<appSettings>    <add key="DBMyTest" value="Data Source=.;Initial Catalog=MyTest;Integrated Security=True"/>  </appSettings>

0 0