using OleDbDataReader class to retrieve a value based on one or more variable values C#.net 2005 winform app

string staff_no = staffDataGridView.CurrentRow.Cells[0].Value.ToString();

string staff_id="";

using (OleDbConnection connection = new OleDbConnection(Properties.Settings.Default.HPMConnectionString))
{
//OleDbCommand findStaffIDCommand = new OleDbCommand("SELECT staff_id FROM staff WHERE staff_no = '" + staff_no + "'", connection);
OleDbCommand findStaffIDCommand = new OleDbCommand( "SELECT staff_id FROM staff WHERE staff_no = @staff_no",connection );
findStaffIDCommand.Parameters.AddWithValue( "@staff_no" , staff_no );

connection.Open();
OleDbDataReader reader = findStaffIDCommand.ExecuteReader();

while (reader.Read())
{
staff_id = (reader[0].ToString());
}
reader.Close();
}
MessageBox.Show( staff_id.ToString() );