#region 1.0 新增 -void Add()

/// <summary>

/// 1.0 新增

/// </summary>

static void Add()

{

    //1.1创建实体对象

    User uObj = new User()

    {

        uName = "刘德华",

        uLoginName = "aaa",

        uPwd = "asdfasdfasdfsadf",

        uIsDel = false,

        uAddtime = DateTime.Now

    };

    //1.2通过EF新增到数据库

    //1.2.1将对象 加入到 数据上下文 的 User集合中

    db.Users.Add(uObj);

    //1.2.2调用数据上下文 的 保存方法，将 对象 存数数据库

    db.SaveChanges();

    Console.WriteLine("保存成功~~！");

}

#endregion

#region 2.0 简单查询 -void Query()

/// <summary>

/// 2.0 简单查询

/// </summary>

static void Query()

{

    List<User> list = db.Users.Where(u => u.uName == "刘德华").ToList();

    list.ForEach(u => Console.WriteLine(u.ToString()));

}

#endregion

#region 3.0 官方推荐的 修改方式（先查询，再修改）

/// <summary>

/// 3.0 官方推荐的 修改方式（先查询，再修改）

/// </summary>

static void Edit()

{

    //1.查询出一个 要修改的对象

    User usr = db.Users.Where(u => u.uId == ).FirstOrDefault();

    Console.WriteLine("修改前：" + usr.ToString());

    //2.修改内容

    usr.uName = "刘德华";

    usr.uLoginName = "liudehua";

    //3.重新保存到数据库

    db.SaveChanges();

    Console.WriteLine("修改成功：");

    Console.WriteLine(usr.ToString());

}

#endregion

#region 4.0 删除 -void Delete()

/// <summary>

/// 4.0 删除

/// </summary>

static void Delete()

{

    //4.1创建要删除的 对象

    User u = new User() { uId =  };

    //4.2附加到 EF中，Remove前必须Attach

    db.Users.Attach(u);

    //4.3标记为删除

    db.Users.Remove(u);

    //4.4执行删除sql

    db.SaveChanges();

    Console.WriteLine("删除成功~~~");

}

#endregion

public partial class User

{

    public override string ToString()

    {

        return this.uId + "," + this.uName + "," + this.uLoginName + "," + this.uPwd;

    }

}

//1.添加(增)

EFDBEntities entity = new EFDBEntities();

Users users = new Users() { username = "aaa", password = "" };

entity.Entry(users).State = EntityState.Added;

entity.SaveChanges();

//2.删除(删)

EFDBEntities entity = new EFDBEntities();

Users users = new Users() { id =  };

entity.Entry(users).State = EntityState.Deleted;

entity.SaveChanges();

//3.修改(改)

EFDBEntities entity = new EFDBEntities();

Users users = new Users() { id = , username = "rrr", password = "" };

entity.Entry(users).State = EntityState.Modified;

entity.SaveChanges();

//4.查询(查)

//获取所有数据

var list = entity.Users;

foreach (var item in list)

{

Console.WriteLine(item.id + "---" + item.username + "---" + item.password);

}

//第一种方法，查询id=1的数据

IQueryable<Users> list1 = from u in entity.Users

where u.id ==

select u;

//第二种方法，查询id=1的数据

IQueryable<Users> list2 = entity.Users.Where(i => i.id == );

//查询第一条数据

Users us = entity.Users.FirstOrDefault();

//遍历

foreach (var item in list1)

{

    Console.WriteLine(item.id + "---" + item.username + "---" + item.password);

}