[英]inner join in linq to entities
我有一個名為 Customer 的實體,它具有三個屬性:
public class Customer {
public virtual Guid CompanyId;
public virtual long Id;
public virtual string Name;
}
我還有一個名為 Splitting 的實體,它具有三個屬性:
public class Splitting {
public virtual long CustomerId;
public virtual long Id;
public virtual string Name;
}
現在我需要編寫一個獲取 companyId 和 customerId 的方法。 該方法應返回與 companyId 中的特定 customerId 相關的拆分列表。 像這樣的東西:
public IList<Splitting> get(Guid companyId, long customrId) {
var res=from s in Splitting
from c in Customer
...... how to continue?
return res.ToList();
}
var res = from s in Splitting
join c in Customer on s.CustomerId equals c.Id
where c.Id == customrId
&& c.CompanyId == companyId
select s;
使用Extension methods
:
var res = Splitting.Join(Customer,
s => s.CustomerId,
c => c.Id,
(s, c) => new { s, c })
.Where(sc => sc.c.Id == userId && sc.c.CompanyId == companId)
.Select(sc => sc.s);
您可以在 Visual Studio 中找到一大堆 Linq 示例。 只需 select Help -> Samples
,然后解壓縮 Linq 示例。
打開 linq 示例解決方案並打開SampleQueries項目的LinqSamples.cs 。
您正在尋找的答案在方法 Linq14 中:
int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };
int[] numbersB = { 1, 3, 5, 7, 8 };
var pairs =
from a in numbersA
from b in numbersB
where a < b
select new {a, b};
不是 100% 確定這兩個實體之間的關系,但這里有:
IList<Splitting> res = (from s in [data source]
where s.Customer.CompanyID == [companyID] &&
s.CustomerID == [customerID]
select s).ToList();
IList<Splitting> res = [data source].Splittings.Where(
x => x.Customer.CompanyID == [companyID] &&
x.CustomerID == [customerID]).ToList();
public IList<Splitting> get(Guid companyId, long customrId) {
var res=from c in Customers_data_source
where c.CustomerId = customrId && c.CompanyID == companyId
from s in Splittings_data_srouce
where s.CustomerID = c.CustomerID
select s;
return res.ToList();
}
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