private void button1_Click(object sender, EventArgs e)
        {
            // 建立连接字符串
            string strconnection = "user id=sa; password=jian0725;";
            strconnection += "initial catalog=Northwind;server=baserker;";
            strconnection += "connect timeout=30;";
            SqlConnection mylink = new SqlConnection(strconnection);
            mylink.Open();
            SqlDataAdapter myadapter = new SqlDataAdapter();
            DataSet mydataset = new DataSet();
            string strcom = "select employeeid,lastname,firstname from employees order by employeeid";
            myadapter.SelectCommand = new SqlCommand(strcom, mylink);
            SqlCommandBuilder mycb = new SqlCommandBuilder(myadapter);
            myadapter.Fill(mydataset, "employees");
            dataGridView1.DataSource = mydataset;                       
            mylink.Close();
        }