private SqlDataAdapter dataAdapter;
            private DataSet ds = new DataSet();


        private void btSaveUpdate_Click(object sender, EventArgs e)
        {
            DialogResult result = MessageBox.Show("确定保存修改吗？","提示",MessageBoxButtons.OKCancel,MessageBoxIcon.Question);
            if (result == DialogResult.OK)
            {
                SqlCommandBuilder builder=new SqlCommandBuilder(dataAdapter);
                dataAdapter.Update(ds, "Teacher");
            }
        }