private void dataGridView1_DataBindingComplete(object sender, DataGridViewBindingCompleteEventArgs e) { for (int i = 0; i < dataGridView1.Rows.Count; i++) dataGridView1.Rows[i].HeaderCell.Value = classNames[i]; dataGridView1.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders; }