using (testEntities db = new testEntities())
{
    //新增
    var person1 = new Person() { Name = "Lily" };
    db.Person.Add(person1);
    var person2 = new Person() { Name = "LiLei" };
    db.Person.Add(person2);
    db.SaveChanges();

    //修改
    var person3 = db.Person.Where(item => item.Id == 1).FirstOrDefault();
    person3.Name = "Lucy";
    db.SaveChanges();

    //遍历
    var data = db.Person;
    foreach (var item in data)
    {
        Console.WriteLine("{0},{1}", item.Id, item.Name);
    }

    //删除
    var person4 = db.Person.Where(item => item.Name == "LiLei").FirstOrDefault();
    db.Person.Remove(person4);
    db.SaveChanges();
}