Linq query for groupby and sum

[ppr (Peter Preuss)]

@Sugumar8785
in that case I would suggest

Groups = (From dte In dtData.AsEnumerable
Group dte By col1=dte(2).ToString.Trim Into grp=Group
Select grp.toList).toList

for Key Columns: grp.First()(KeyColumnNameOrIndex)
for Aggregations e.g Sum: grp.Sum(Function (x) CInt(x(ColIndexOrName).toString.Trim))

This split allows you a more control on bug fixing and maintenance