this may be a  other solution: in WebDataGrid  You must set 

EnableDataViewState="True"  ViewStateMode="Enabled"  AND Open selection option

<ig:Selection CellClickAction="Row" RowSelectType="Single" ….>

foreach (Infragistics.Web.UI.GridControls.GridRecord r in WebDataGrid1.Behaviors.Selection.SelectedRows)
{
   if (r != null)
   {

       XX = r.Items[WebDataGrid1.Columns["Name"].Index].Value.ToString(); //well be get Cell value or text

    }

}