private void dgvClass_UserDeletingRow(object sender, DataGridViewRowCancelEventArgs e) { int id = 0; if (int.TryParse(e.Row.Cells[0].Value.ToString(), out id)) { var db = new LINQDataContext(); db.Priority_ProfessorDeleteClass(id); db.Classroom_TimeDeleteClass(id); db.Group_ID_ListDeleteClass(id); db.ClassDelete(id); db.Dispose(); } }