Linq C# Group by Sum

See more:

C#

LINQ

Actual Data

ID | Qty | UnitPrice
1 2 10.00
1 3 30.00


I wanna group by this table with same ID, but it show put two row of output like this

Fail Output
ID | Total
1 20.00
1 90.00

but actually i wish my output is like this

ID | Total
1 110.00

pls kindly advise cause i still new in linq , thank alot

   public DataTable GetQuotationInfo(int QuotationId)
        {

            FADB db = new FADB();

            DataTable dt = new DataTable();
            dt.Columns.Add("QuotationId");
            dt.Columns.Add("ServiceOrderNo");
            dt.Columns.Add("Date");
            dt.Columns.Add("Name");
            dt.Columns.Add("OnwerAddress");
            dt.Columns.Add("QuotationNo");
            dt.Columns.Add("Premises");
            dt.Columns.Add("PayableTo");
            dt.Columns.Add("Total");
            dt.Columns.Add("Qty");
            dt.Columns.Add("UnitNo");
            dt.Columns.Add("Status");




            dt = (from q in db.Csm_quotations 
                  join j in db.Csm_quotation_jobs on q.QuotationId equals j.QuotationId 
                  join c in db.Csm_complaints on q.ComplaintId equals c.ComplaintID
                  join f in db.Fa_lots on c.UnitId equals f.UnitId 
                  join o in db.Sys_owners on f.OwnerId equals o.OwnerId

                  group new { q,j,c,f,o } by new { q.QuotationId,c.ComplaintCode,q.QuotationDate,q.QuotationSubject,q.PayableTo,q.Status,f.OwnerAddress,f.Address,o.OwnerName,j.Qty,j.UnitPrice }
                  into grp
                  where grp.Key.QuotationId == Convert.ToUInt16(QuotationId)
                 select new
                  {
           
                QuotationId = grp.Key.QuotationId,
                ServiceOrderNo = grp.Key.ComplaintCode,
                Date = grp.Key.QuotationDate.ToString("dd/MM/yyyy"),
                Name = grp.Key.OwnerName,
                OnwerAddress =grp.Key.OwnerAddress,
                QuotationNo = grp.Key.QuotationSubject,
                Premises = grp.Key.Address,
                PayableTo = grp.Key.PayableTo,

                Total = Convert.ToDouble(grp.Sum(x => (grp.Key.Qty * grp.Key.UnitPrice))) // as i know this line having problem, pls giving any suggestion  

      

                  }).ToDataTable();
            return dt;
}