ADO.NET Entity Framework,Code First简单示例
一、安装EntityFramework;
在vs里打开NuGet,在命令行里输入:Install-Package EntityFramework。
二、基本使用方法
1.建立数据模型
class Student { public int id { get; set; }//ID public string name { get; set; }//姓名 public byte age { get; set; }//年龄 }
2.建立数据上下文
using System.Data.Entity;//引用Entity Framework namespace Sql { class StudentContext:DbContext { public StudentContext() : base(@"Data Source=MYPC\MSSQLSERVER;Initial Catalog=entitycodefirst;User ID=sa;Password=123456") { } public DbSet<Student> Students { get; set; } } }
3.使用
using System; namespace Sql { class Program { static void Main(string[] args) { //保存 using (var data=new StudentContext()) { var student1 = data.Students.Create();//创建一个学生的对象 student1.name = "小曼"; student1.age = 15; data.Students.Add(student1);//将学生对象加入学生表中 var student2 = data.Students.Create(); student2.name = "小红"; student2.age = 15; data.Students.Add(student2); data.SaveChanges();//保存进数据库里 } //读取 using (var data = new StudentContext()) { foreach (var item in data.Students) { Console.WriteLine("ID:{0},姓名:{1},年龄:{2}",item.id,item.name,item.age); } } Console.ReadKey(true); } } }
Database.SetInitializer<MvcAppEF.Sql.StudentContext>(null);
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace MvcAppEF.Models
{
public class Student
{
public int id { get; set; }//ID
public string name { get; set; }//姓名
public int age { get; set; }//年龄
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Text;
using MvcAppEF.Sql;
namespace MvcAppEF.Controllers
{
public class HomeController : Controller
{
public ActionResult Index()
{
ViewBag.Message = "Modify this template to jump-start your ASP.NET MVC application.";
return View();
}
public ActionResult About()
{
ViewBag.Message = "Your app description page.";
return View();
}
public ActionResult Contact()
{
ViewBag.Message = "Your contact page.";
return View();
}
public String Main()
{
StringBuilder sbOutput = new StringBuilder();
//保存
using (var data = new StudentContext())
{
var student1 = data.Students.Create();//创建一个学生的对象
student1.name = "小曼";
student1.age = 15;
data.Students.Add(student1);//将学生对象加入学生表中
var student2 = data.Students.Create();
student2.name = "小红";
student2.age = 15;
data.Students.Add(student2);
data.SaveChanges();//保存进数据库里
}
//读取
using (var data = new StudentContext())
{
foreach (var item in data.Students)
{
sbOutput.Append(String.Format("ID:{0},姓名:{1},年龄:{2}<BR />\r\n", item.id, item.name, item.age));
}
}
//Console.ReadKey(true);
return sbOutput.ToString();
}
}
}