can i get a hidden column value from a datagridview during runtime

yes you can do it by casting data gridview data source into its original data type.
then you can access all public attribute in case of List and
all the column if you cast Grid DataView into DataTable

if(datagridview.DataSource as DataTable){

    DataTable dt = datagridview.DataSource as DataTable;
   // Now You can access all the Column of data Table.
}