使用LINQ to組由多個屬性和金額

Question

我有項目的集合，在這裏它是：

AgencyID VendorID StateID Amount Fee 
1  1  1  20.00 5.00 
1  1  1  10.00 2.00 
1  1  1  30.00 8.00  
2  2  1  20.00 5.00 
2  2  1  5.00 5.00 
1  1  2  20.00 5.00 
2  2  2  20.00 5.00 
2  2  2  40.00 9.00 
1  2  2  35.00 6.00 
1  2  2  12.00 3.00 

我想這些項目立足於AgencyID，廠商ID，並STATEID分組，從金額和手續費（金額+手續費）計算的總

因此，在使用上述數據，我想有以下結果：

AgencyID VendorID StateID Total 
1  1  1  75.00  
2  2  1  35.00 
1  1  2  25.00 
2  2  2  74.00 
1  2  2  56.00 

這就是我現在所擁有的，它只是得到每一行在數據中基地：

var agencyContracts = _agencyContractsRepository.AgencyContracts. 
    Select(ac => new AgencyContractViewModel 
    { 
     AgencyContractId = ac.AgencyContractID, 
     AgencyId = ac.AgencyID, 
     VendorId = ac.VendorID, 
     RegionId = ac.RegionID, 
     Amount = ac.Amount, 
     Fee = ac.Fee 
    }); 

有誰知道我怎麼可以過濾和分組與LINQ？

Answer 1

使用.Select()分組後：

var agencyContracts = _agencyContractsRepository.AgencyContracts 
    .GroupBy(ac => new 
        { 
         ac.AgencyContractID, // required by your view model. should be omited 
              // in most cases because group by primary key 
              // makes no sense. 
         ac.AgencyID, 
         ac.VendorID, 
         ac.RegionID 
        }) 
    .Select(ac => new AgencyContractViewModel 
        { 
         AgencyContractID = ac.Key.AgencyContractID, 
         AgencyId = ac.Key.AgencyID, 
         VendorId = ac.Key.VendorID, 
         RegionId = ac.Key.RegionID, 
         Amount = ac.Sum(acs => acs.Amount), 
         Fee = ac.Sum(acs => acs.Fee) 
        }); 

Answer 2

萊納斯是在接近現貨，但幾個屬性都關閉。它看起來像'AgencyContractId'是你的主鍵，它與你想給用戶的輸出無關。我認爲這是你想要的（假設你改變你的ViewModel以匹配你在視圖中說的數據）。

var agencyContracts = _agencyContractsRepository.AgencyContracts 
    .GroupBy(ac => new 
        { 
         ac.AgencyID, 
         ac.VendorID, 
         ac.RegionID 
        }) 
    .Select(ac => new AgencyContractViewModel 
        { 
         AgencyId = ac.Key.AgencyID, 
         VendorId = ac.Key.VendorID, 
         RegionId = ac.Key.RegionID, 
         Total = ac.Sum(acs => acs.Amount) + ac.Sum(acs => acs.Fee) 
        });