给DataGridView 添加鼠标单击事件，并且在contexMenutstrip中显示，获取该行的主键

   private void dataGridViewEx1_MouseClick(object sender, MouseEventArgs e)

        {

            if(e.Button==MouseButtons.Right)

            {

                contextMenuStrip3.Show(dataGridViewEx1, 0, e.Y);
            }

        }
        private void toolStripMenuItem_Delete_Click(object sender, EventArgs e)

        {

            if(MessageBox.Show("确定要删除该条记录吗？","提示",MessageBoxButtons.YesNo)==DialogResult.Yes)  //messbox的show方法的使用

            {

                int MXid = DbUtils.GetInt(dataGridViewEx1.CurrentRow.Cells[0].Value.ToString());      
//右键点击所在的行

                DAL.TorchLabQuery.DeleteMXid(MXid);

            }

            BindGridMX(tb_RN.Text);

        }