how to match excel sheet with datagridview in winforms

Please check this:
http://social.msdn.microsoft.com/Forums/vstudio/en-US/522a1032-fe8b-4290-abb1-b2e8fe11ee9b/best-and-faster-way-in-searching-between-datagridview-and-an-excel-sheet

OR 

http://stackoverflow.com/questions/11962371/how-to-compare-between-data-in-datagridview-and-data-in-excel-file-invb