Linq GroupBy和Sum在两个字段上 [英] Linq GroupBy and Sum over two fields

问题描述

我有一个三列表，我想按第一列和第二列进行分组，并对第三列求和.

Linq有可能吗?如果是这样，语法是什么，我找到了一个单列groupby，但看不到如何扩展它.

I''ve got a three column table, I would like to group by the first and second columns and sum the third.

Is this possible in Linq? If so what is the syntax, I''ve found for a single column groupby but can''t see how to expand it.

推荐答案

尝试一下， http://www.devcurry.com/2009/02/groupby-multiple-values- in-linq.html [ ^ ]或 http://msdn.microsoft.com/en-我们/library/bb534743.aspx [ ^ ]

Try this, http://www.devcurry.com/2009/02/groupby-multiple-values-in-linq.html[^] or this, http://msdn.microsoft.com/en-us/library/bb534743.aspx[^]

谢谢，我现在可以正常工作了:

Thanks, I''ve got that working now:

var query = feeAllRecords
    .GroupBy(f => new { f.AccountNo, f.FeeTypeID })
    .Select(group => new { fee = group.Key, total = group.Sum(f => f.FeeAmount) });

目前，我正在遍历此结果集以转换为最终结果集:

At the moment I''m then looping through this result set to convert to my final result set:

List<inFee> feeRecords = new List<inFee>(feeAllRecords.Capacity);
foreach (var rec in query)
{
    inFee fee2 = new inFee();
    fee2.AccountNo = rec.fee.AccountNo;
    fee2.FeeTypeID = rec.fee.FeeTypeID;
    fee2.FeeAmount = rec.total;

    feeRecords.Add(fee2);
}

它有效，但似乎不正确"，或者至少应该有一种更有效的方法?

It works, but it seems ''incorrect'', or at least that there should be a more efficent method??

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