Question

I’m running the query below :-

var Values = from data in DtSet.Tables["tblCosts"].AsEnumerable()
            group data by new
            {
                InvNo = data.Field<double>("InvoiceNo"),
                AccRef = data.Field<double>("SiteRefNum"),
            }
            into g
            select new
            {
                Code = "1",
                InvType = "I",
                Account = g.Key.AccRef,
                InvNo = g.Key.InvNo,
                ChargeTotal = g.Sum(d => d.field<double>("Charge")
            };

Due to the way the data is imported into the datatable (from Excel) sometimes the datatype of AccRef is double and sometimes it’s string. Is there a way to overcome this at runtime, as I’d prefer to not have the user modify the source data in Excel before importing.

Answer 1

You can use Convert.ToDouble with objects, so it should work for double and for string:

var Values = from data in DtSet.Tables["tblCosts"].AsEnumerable()
             group data by new
             {
                 InvNo = data.Field<double>("InvoiceNo"),
                 AccRef = Convert.ToDouble(data["SiteRefNum"]),
             }
             into g
             select new
             {
                 Code = "1",
                 InvType = "I",
                 Account = g.Key.AccRef,
                 InvNo = g.Key.InvNo,
                 ChargeTotal = g.Sum(d => d.Field<double>("Charge"))
             };

Of course that works only if SiteRefNum is actually convertable to a double.