Convert IEnumerable to Sum item Linq-CodePudding

I need to convert an IEnumerable to something else to be able to use Sum. What can I do to achieve this?

CsTotCommit = h.Sum(x => x.CSTotCommit)

I receive an error stating that: CapStackTrancheDTO does not contain a definition for 'Sum' accepting a first argument of type CapStackTrancheDTO.

        IEnumerable<CapStackTrancheDTO> debtRank = debt.AsEnumerable()
                        .Select((g,index) =>
                        new CapStackTrancheDTO
                        {
                            Rankid = index   1,
                            CsTrancheId = g.CsTrancheId,
                            CsId = g.CsId,
                            CsTotCommit = g.CsTotCommit,
                        });


        IEnumerable<CapStackTrancheDTO> debtSum = debtRank
                      .Select(h =>
                      new
                      {
                          CsId = h.CsId,
                          CsTotCommit = h.Sum(x => x.CSTotCommit)
                      });

Here are the class defintions:

public class CapStackTrancheDTO
{
    public int? Rankid { get; set; }
    public int? CsTrancheId { get; set; }
    public int? CsId { get; set; }
    public decimal? CsTotCommit { get; set; }

}

There are multiple records which I want to group by CsId and SUM.

CodePudding user response：

From the comments, you've said that you want to group by CsId and then sum.

Currently, you're not applying any grouping.

Use the .GroupBy method, like this:

IEnumerable<CapStackTrancheDTO> debtSum = debtRank
    .GroupBy(h => h.CsId)
    .Select(h =>
        new CapStackTrancheDTO
        {
            CsId = h.Key, // the value we grouped on above is now available in `Key`
            CsTotCommit = h.Sum(x => x.CSTotCommit)
        }
   );