private void dataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
        {//选中单元格，弹出快捷菜单。
            if (e.Button == MouseButtons.Right)
            {
                if (e.RowIndex >= 0)
                {
                    this.dataGridView1.ClearSelection();
                    this.dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Selected = true;
                    this.dataGridView1.CurrentCell = dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex];  //右击时选中
                    contextMenuStrip1.Show(MousePosition.X, MousePosition.Y);
                }