EF 简单的 CRUD、分页 代码笔记

添加：
 static void Main(string[] args)
        {
            CCDBEntities ccdbContext = new CCDBEntities();

            MyStudent user = new MyStudent();
  
            user.FName = "胡章诚";
            user.FAge = 21;
            user.FGender = "男";
            user.FMath = 88;
            user.FEnglish = 99;
            user.FClassId = 2;
            user.FBirthday = DateTime.Now;

           
            ccdbContext.MyStudent.Add(user);
            ccdbContext.SaveChanges();
        }

-----------------------------------
修改整个表实体

 static void Main(string[] args)
        {
            CCDBEntities ccdbContext = new CCDBEntities();

            MyStudent user = new MyStudent();
            user.Fid = 21;   //注：修改的时候要为主键赋值
            user.FName = "胡章诚";
            user.FAge = 21;
            user.FGender = "男";
            user.FMath = 88;
            user.FEnglish = 99;
            user.FClassId = 2;
            user.FBirthday = DateTime.Now;

            ccdbContext.MyStudent.Attach(user);
            ccdbContext.Entry<MyStudent>(user).State = System.Data.EntityState.Modified;
            ccdbContext.SaveChanges();
        }

----------------------------------------

修改一个列：
 static void Main(string[] args)
        {
            CCDBEntities ccdbContext = new CCDBEntities();

            MyStudent user = new MyStudent();
            user.Fid = 22;
            user.FName = "胡章诚";
            user.FAge = 21;
            user.FGender = "男";
            user.FMath = 88;
            user.FEnglish = 99;
            user.FClassId = 2;
            user.FBirthday = DateTime.Now;

            ccdbContext.MyStudent.Attach(user);
            ccdbContext.Entry<MyStudent>(user).Property<string>(u => u.FName).IsModified = true;
            ccdbContext.SaveChanges();

            Console.WriteLine("修改成功");
            Console.ReadKey();
        }
-------------------------------------------
删除一条数据：
  static void Main(string[] args)
        {
            CCDBEntities ccdbContext = new CCDBEntities();

            MyStudent user = new MyStudent();
            user.Fid = 22;

            ccdbContext.MyStudent.Attach(user);
            ccdbContext.Entry<MyStudent>(user).State = System.Data.EntityState.Deleted;
            ccdbContext.SaveChanges();
        }

-----------------------------------------

查询：

1、用Lambda进行查询

            var modelList = dbContext.MyStudent
                .Where(u => u.Fid < 100)
                .Where(u => u.Fid > 40)
                .Select(u => new { u.Fid, u.FName, u.FGender });

2、用linq查询
            var modelList = from u in dbContext.MyStudent
                            where u.Fid > 40 && u.Fid < 100
                            select new { u.FGender, u.Fid };

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分页：

采用 Lambda表达式 分页:
            var modelList = dbContext.MyStudent
                .OrderBy(u=>u.Fid)
                .Skip(pagesize * (pageIndex - 1))
                .Take(pagesize);