Hello, Thanks for indicating the way. Actual code is tblMaster.Columns("Id").ColumnMapping = MappingType.Hidden tblMaster.Columns("IsBillable").ColumnMapping = MappingType.Hidden where "tblMaster" is datatable, it does work and seems to be correct way of doing this. Now I am trying to see how the hidden columns will be updated when foreign key values change due to change in name/description of foreign key or when a new record is added. I will post the concerned code when I check it thoroughly. thanks once again.
thanks, Madhav