datagridview 右键选中行 并弹出菜单

private void dataGridView_OLUsers_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)

        {

            if (e.Button == MouseButtons.Right)

            {

                if (e.RowIndex >= 0)

                {

                    dataGridView_OLUsers.ClearSelection();

                    dataGridView_OLUsers.Rows[e.RowIndex].Selected = true;

                    dataGridView_OLUsers.CurrentCell = dataGridView_OLUsers.Rows[e.RowIndex].Cells[e.ColumnIndex];

                    contextMenuStrip1.Show(MousePosition.X, MousePosition.Y);

                }

            }

        }