我有这个:
var q = (from order in db.Orders
from payment in db.Payments
.Where(x => x.ID == order.paymentID)
.DefaultIfEmpty()
from siteUser in db.SiteUsers
.Where(x => x.siteUserID == order.siteUserID)
.DefaultIfEmpty()
where siteUser.siteUserID != null
select new
{
order.orderID,
order.dateCreated,
payment.totalAmount,
siteUser.firstName,
siteUser.lastName
});
我想这样补充:
switch (_qs["sort"])
{
case "0":
q = q.OrderByDescending(x => x.dateCreated);
break;
case "1":
q = q.OrderBy(x => x.dateCreated);
break; ...
我以前用一个表做过这件事,但第一个代码块中的多个表迫使我指定一个select语句,使其成为匿名类型。如何做到这一点?
注意:我甚至尝试用我选择的属性创建一个类,并将查询强制转换为这种类型,但仍然没有成功。
不确定我是否理解这个问题,但你粘贴的代码对我来说是有效的。
我检查过:
var q = (
from order in db.Orders
join payment in db.Payments on
order.paymentID equals payment.ID into payments
from payment in payments.DefaultIfEmpty()
join siteUser in db.SiteUsers on
order.siteUserID equals siteUser.siteUserID into siteUsers
from siteUser in siteUsers.DefaultIfEmpty()
where siteUser.siteUserID != null
select
new
{
order.orderID,
order.dateCreated,
payment.totalAmount,
siteUser.firstName,
siteUser.lastName
});
switch (sort)
{
case "0":
q = q.OrderByDescending(x => x.dateCreated);
break;
case "1":
q = q.OrderBy(x => x.dateCreated);
break;
}
var restult = q.ToList();
这是有效的。