从DataSet 返回XML 数据

DataSet 常用操作Xml方法有DataSet.WriteXml()、DataSet.ReadXml()、DataSet.GetXml()

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.Data.SqlClient;using System.Xml;using System.Xml.XPath;namespace UsingDataSet{    public partial class Form1 : Form    {        string strSQL = null;        DataSet ds = null;        public Form1()        {            InitializeComponent();        }        private void loadFromToolStripMenuItem_Click(object sender, EventArgs e)        {            strSQL = @"SELECT  [ProductID]                              ,[ProductName]                              ,[SupplierID]                              ,[CategoryID]                              ,[QuantityPerUnit]                              ,[UnitPrice]                              ,[UnitsInStock]                              ,[UnitsOnOrder]                              ,[ReorderLevel]                              ,[Discontinued]                          FROM [Products]";           ds =SqlHelper.ExecuteDataSet(CommandType.Text, strSQL);           dataGridView1.DataSource = ds.Tables[0];        }                   //WriteXml        private void saveToFileToolStripMenuItem_Click(object sender, EventArgs e)        {            SaveFileDialog sfd = new SaveFileDialog();            if (DialogResult.OK == sfd.ShowDialog())            {                string fileName = sfd.FileName;                //this.ds.WriteXml(fileName, XmlWriteMode.WriteSchema);                this.ds.WriteXml(fileName, XmlWriteMode.DiffGram);            }        }        //ReadXml        private void loadFromFileStripMenuItem_Click(object sender, EventArgs e)        {            OpenFileDialog ofd = new OpenFileDialog();            if (DialogResult.OK == ofd.ShowDialog())            {                string fileName = ofd.FileName;                this.ds.ReadXml(fileName, XmlReadMode.ReadSchema);                dataGridView1.DataSource = this.ds.Tables[0];            }        }        //GetXml        private void getXmlToolStripMenuItem_Click(object sender, EventArgs e)        {            MessageBox.Show(this.ds.GetXml());        }                  }}