I have a datatable with the records.I\'m inserting records into Sql table using SqlBulkCopy.It works fine.Next time when get the datatable with same records with few changed
SqlBulkCopy is only used for inserting records, not updating them as explained here. You'd need to use a different technique to do bulk updates.
e.g. you could SqlBulkCopy into a staging table, then run some SQL to update from there to the main table.