using (DataContext ctx = new DataContext())

{

/*foreach (var item in ctx.employees)

{

ViewData["Name"] = item.Name;

}

*/

//------------------------------------------

/*var employees = from emp in ctx.employees

where emp => emp.Age == 22 && emp.ID == "123456781"

select emp;

//上边转化

var employees = ctx.employees.Where(emp => emp.Age == 22 && emp.ID == "123456781");

foreach (var item in employees)

{

ViewData["Name"] = item.Name;

}--------------------------------------------*/

/*---------------------------------------

* var employees = from emp in ctx.employees

where emp.Age == 22 && emp.ID == "123456781"

select emp.Name;//查询单个字段

var employees = ctx.employees.Where(emp => emp.Age == 22 && emp.ID == "123456781")

.OrderBy(emp => emp.ID)

.Select(emp => emp.Name);//查询单个字段

//---------------------------------------------------

var employees2 = from emp in ctx.employees

where emp.Age == 21

select new { emp.Age, emp.Name };//查询多个字段*/

/*var employees2 = ctx.employees

.Where(emp => emp.Age == 21)

.OrderBy(emp => emp.Age)

.Select(emp => new { emp.Name, emp.Age });//查询多个字段

//----------------------------------------------

/不管怎样都要用foreach、

foreach (var item in employees)

{

ViewData["single"] = item;//因为它查出来是单个字段，所以直接输出,不用点了

}

foreach (var item in employees2)

{

ViewData["doubleAge"] = item.Age;

ViewData["doubleName"] = item.Name;//他很智能的。

}

//------------------------------------

var employees = ctx.employees.Find("123456781");

if (employees != null)

{

ViewData["df"] = employees;

}

//加载数据到内存中,加载完了就可以用Local了

ctx.employees.Load();

var employees = from employee in ctx.employees.Local select employee;

foreach (var item in employees)

{

ViewData["fsdf"] = item;

}

//inclue 贪婪查询。

var employees = ctx.employees.Include(p => p.department);

foreach (var item in employees)

{

ViewData["dep"] = item.department.DepName;

ViewData["empName"] = item.Name;

}*/

var employees = ctx.employees.Include(emp=>emp.department).ToList();//查询列表

ViewData.Model = employees;

return View();

 

 

外键数据保存：

public ActionResult AddHandler(int droplist, Employee emp)

{

using (DataContext dbcontext=new DataContext ())

{

int did = droplist;

Department dep = new Department();

dep = dbcontext.dempartments.Find(did);//先找到外键实体

emp.department = dep;//因为emp中外键是一个实体，所以你要给实体，不能只给ID外键。

dbcontext.employees.Add(emp);

dbcontext.SaveChanges();

return RedirectToAction("List");

}

}

}