Hi Vivien,
You can try adding an additional column to the table to hold the additional data for each row and make that column hidden in the grid.
Or you could have an HashTable, which takes the primary key of the corresponding row as the hashkey and the associated tagvalue as the hashValue. You can retrieve the corresponding hashvalue anytime while processing a datarow.
Is that, your requirement is to process when the user moves from one record to another record?. If so then you can use the CurrentRecordContextChange event. From this event's argument you can get the corresponding DataRowView of the binded DataTable.
Please refer to this sample.
http://websamples.syncfusion.com/samples/Grid.Windows/F62497/main.htmBest Regards,
Saravanan