private void dataGridView1_RowHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
        {
            dataGridView1.Rows[e.RowIndex].Cells[0].Selected = true;
        }

------解决方案--------------------
private void dataGridView1_RowHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
       {
           dataGridView1.Rows[e.RowIndex].Cells[0].Selected = true;
       }