鼠標右鍵選中行

 轉自：https://www.cnblogs.com/dekevin/p/3626944.html

事件是  CellButtonDown

private void HandleCellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
        {
            if (e.Button == MouseButtons.Right && e.RowIndex > -1 && e.ColumnIndex > -1)
            {

                (sender as DataGridView).CurrentRow.Selected = false;

                (sender as DataGridView).Rows[e.RowIndex].Selected = true;

            }
        }