OOPs.. I Don't have to do it again

This functionality is missing in the GridView control. There are various ways to go about it. I thought I will do it without Ajax or other overheads. The following code takes in a Datatable as input and returns the grouped Datatable as output. Make the output datatable the source of any gridview! The parameters allow multi column grouping and sorting becomes -----------------------------------------------------------------------   Public Shared Function GroupDataTable(ByVal T1 As DataTable, ByVal GroupByColumns As String(), _     Optional ByVal SortOrder As Boolean() = Nothing, _     Optional ByVal SumColumns As String() = Nothing, _     Optional ByVal HeaderCell As Integer = 0 _     ) As DataTable         Dim T2 As New DataTable         Dim sortStr As String = ""       ...