分类:
.NET MVC
1、left join 用GroupJoin来实现，join的返回结果为一对一，GroupJoin返回结果为一对多，相当于集合中还有集合
public ActionResult Index()
{
//left join (lamdba写法)
var result = oae.userinfo.GroupJoin(oae.noteinfo, a => a.userId, b => b.userId, (u, n) => new
{
userName = u.userName,
notes = n
}).SelectMany(a => a.notes.DefaultIfEmpty(), (a, b) => new
{ userName = a.userName,
noteRemark = b.noteRemark
}).ToList();
List<users> list = new List<users>();
foreach (var item in result)
{
users user = new users();
user.userId = item.userId;
user.userName = item.userName;
user.noteRemark = item.noteRemark;
list.Add(user);
}
ViewBag.count = list.Count;
return View(list);
}a为上一次返回结果，b为前一个表，SelectMany方法返回一个实体集合，再把返回结果解析到一个具体的实体集合，再返回给前台，在前台就可以显示数据了。（自我理解）
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