（家产2分全给出）如何将datagridview的修改更新的数据库（datagridview是两个表的联合检索）

Question

datagridview是两个表的联合检索,现在想更新其中的数据按更新按钮更新数据库   怎么操作啊，求解！！ public void SQLCheck()//查询
        {
            try
            {
                //创建连接
                String connStr = @"server=192.169.1.234;uid=EDSDBCC;pwd=EDSDBCC;database=EDS";
                //String connStr = @"server='" + SErverIP + "';database=EDS;Integrated Security=True";
                SqlConnection sqlconn = new SqlConnection(connStr);
                sqlconn.Open();
                SqlCommand cmd = new SqlCommand(); //创建命令对象                                                                      
                DateTime dtpselect = new DateTime();
                DateTime dtpselect1 = new DateTime();
                dtpselect = dtpSelectB.Value;
                dtpselect1 = dtpSelectE.Value;                string sqlstr = "select EDS.dbo.ApplyEvection.DepartmentName as '部门名称',ArchivesBasicInfo.Name as '姓名', " +
                                " EvectionApplyBeginDate as '开始时间',EvectionApplyEndDate as '结束时间',beginAddress as '出发地点',EndAddress as '目的地点'" +
                                " FROM EDS.dbo.ApplyEvection  " +
                                " JOIN EDS.dbo.ArchivesBasicInfo  on ArchivesBasicInfo.ArchivesId = ApplyEvection.ArchivesId " +
                                " where Datediff(dy,'" + dtpselect + "',EvectionApplyBeginDate)>0 " +
                                " and Datediff(dy,'" + dtpselect1 + "',EvectionApplyEndDate)<0 " +
                                " and Datediff(dy,EvectionApplyBeginDate,EvectionApplyEndDate)>0 " +
                                " " + Andd + " " + Depart + " " + Cmbox + "" + Anddd + " " + Tbbianliang + " " +   //这些事变量
                                " ORDER BY EDS.dbo.ApplyEvection.DepartmentName"; 
                cmd.CommandText = sqlstr;
                this.textBox3.Text = sqlstr;                cmd.Connection = sqlconn; //指定连接对象，即前面创建的 
                SqlDataAdapter dbAdapter = new SqlDataAdapter(cmd); //注意与上面的区别 
                DataSet ds = new DataSet(); //创建数据集对象 
                dbAdapter.Fill(ds, "baobiao2"); //用返回的结果集填充数据集                DataTable dt = ds.Tables["baobiao2"];
                dataGridView2.DataSource = dt;            }
            catch (Exception)
            {
                
                throw;
            }
}
private void btUpdate_Click(object sender, EventArgs e)
        {
            
            DialogResult result = MessageBox.Show("确实要保存您对数据的修改吗？", "提示", MessageBoxButtons.OKCancel, MessageBoxIcon.Question);
            if (result == DialogResult.OK)//即确认修改的保存
            {
                //这里怎么写啊？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？
            }
        }