LINQ到基于组总结两列

Question

我有如下的类：

Class Financial 
{ 
    string Debit; 
    string Credit; 
    decimal Amount; 
} 

而且我有这个类的对象列表，多个记录。所有我需要的是像SQL

Select debit, Credit, sum(amount) group by Debit, Credit 

我有如下的声明试图进行细分电子邮件总和，东西：

from operation in m_listOperations 
    orderby operation.Debit, operation.Credit ascending 
    group operation by operation.Debit, operation.Credit into groupedOperation 
    select new Financial(Debit, Credit, 
       groupedOperation.Sum(operation => operation.Amount)) 

但是，这并不工作，因为我不能在两列组。

有什么建议吗？

Answer 1

... 
group operation by new { operation.Debit, operation.Credit } into groupedOperation 
...