C# 按Linq分组时更改原始表值

我有一个linq查询，它执行3个group BY。我要做的是将null值和0值分组在一起。或者将特定列中的所有空值更改为0。并获取具有0的组的计数。我还想给包含0的组分配一个“NA”值

我想要得到的是“HowMuchSpent”组对于空值显示为0，以及“Count”将它们包含在一个组中。任何帮助都会很好。提前谢谢

我的问题如下：

var MAList = 
    (
        from vwBudgetPop in dbContext.vw_MonitoringAsst_Budget_PO
        join clientfile in dbContext.ClientFiles on vwBudgetPop.ClientFile_ID equals clientfile.ID  
        group vwBudgetPop by new { clientfile.CountryID_DestinationCountry } into grouped                                                       
        join clientfile2 in dbContext.ClientFiles on grouped.FirstOrDefault().ClientFile_ID equals clientfile2.ID
        join country in dbContext.Countries on clientfile2.CountryID_DestinationCountry equals country.ID

        select new
        {
            Country = clientfile2.Country2.Country1 ?? "NA",
            ChoiceList = from maX in grouped
            group maX by maX.Choice_ID into g2                                              
            join choice in dbContext.Choices on g2.FirstOrDefault().Choice_ID equals choice.ID 

            select new
            {
                Choice = choice.Choice123,
                HmSpentList = 
                    from gd in g2                                                                 
                    group gd by gd.HowMuchSpent_ID  into hmGroup                                                                
                    join hmSpent in dbContext.HowMuchSpents on hmGroup.FirstOrDefault().HowMuchSpent_ID equals hmSpent.ID into hmSpentfull
                    from hm in hmSpentfull.DefaultIfEmpty()
                    select new
                    {
                        HowMuchSpent = hmSpentfull.FirstOrDefault().HowMuchSpent1,
                        Count = hmGroup.Count()
                    }
            }
        }
    ).ToList();

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错误是什么？或者您得到的输出是什么？我得到的输出分组如下-选项1:。我想要得到的是-Choice 1:错误是什么？或者您得到的输出是什么？我得到的输出分组如下-选项1:。我想要得到的是-Choice 1: