在代码中,注释部分是我需要解决的问题...有没有办法在LINQ中编写这样的查询?我需要这个,因为我需要根据状态进行排序。
var result = (
from contact in db.Contacts
join user in db.Users on contact.CreatedByUserID equals user.UserID
join deal in db.Deals on contact.ContactID equals deal.ContactID into deals
orderby contact.ContactID descending
select new ContactListView
{
ContactID = contact.ContactID,
FirstName = contact.FirstName,
LastName = contact.LastName,
Email = contact.Email,
Deals = deals.Count(),
EstValue = deals.Sum(e => e.EstValue),
SalesAgent = user.FirstName + " " + user.LastName,
Tasks = 7,
// This is critical part
if(Deals == 0) Status = "Prospect";
else
Status = "Client";
// End of critical part...
})
.OrderBy(filterQuery.OrderBy + " " + filterQuery.OrderType)
.Where(filterQuery.Status);
答案 0 :(得分:10)
Status = (deals.Count() == 0 ? "Prospect" : "Client")
条件运算符(?:)返回 两个值中的一个取决于 布尔表达式的值。
修改:您可以制作如下组合:
Status = (deals.Count() == 0 ? "Prospect" : (deals.Count() == 1 ? "Client" : "Other"))
在这种情况下,您经常使用deals.Count(
),因此您可以使用LINQ let
语法将结果存储在临时变量中:
var result = (
from contact in db.Contacts
join user in db.Users on contact.CreatedByUserID equals user.UserID
join deal in db.Deals on contact.ContactID equals deal.ContactID into deals
let dealCount = deals.Count()
... // Continue here
Status = (dealCount == 0 ? "Prospect" : (dealCount == 1 ? "Client" : "Other"))
答案 1 :(得分:4)
// This is critical part
Status = deals.Any() ? "Client" : "Prospect"
// End of critical part...
答案 2 :(得分:2)
ar result = (
from contact in db.Contacts
join user in db.Users on contact.CreatedByUserID equals user.UserID
join deal in db.Deals on contact.ContactID equals deal.ContactID into deals
orderby contact.ContactID descending
select new ContactListView
{
ContactID = contact.ContactID,
FirstName = contact.FirstName,
LastName = contact.LastName,
Email = contact.Email,
Deals = deals.Count(),
EstValue = deals.Sum(e => e.EstValue),
SalesAgent = user.FirstName + " " + user.LastName,
Tasks = 7,
// This is critical part
Status = deals.Count()==0 ? "Prospect" : "Client",
// End of critical part...
})
.OrderBy(filterQuery.OrderBy + " " + filterQuery.OrderType)
.Where(filterQuery.Status);