private void btnExport_Click(object sender, EventArgs e) { if (ControlAdmin.SelectedIndex == -1) { return; } if (ControlAdmin.TabPages[ControlAdmin.SelectedIndex] == TabList_student || ControlAdmin.TabPages[ControlAdmin.SelectedIndex] == TabList_teacher) { BUS_Admin.btnExport_Click(_inputParameter, bgWorker_Export, dt_student, dt_teacher, ControlAdmin, TabList_student, TabList_teacher, pgBar); } else { return; } }