XmlReader 读取器读取内存流 MemoryStream 的注意事项

       MemoryStream对象提供了无需进行IO就可以创建Stream的方法，XmlTextWriter和XmlReader提供快速书写和读 取XML内容的方法，结合MemoryStream，就可以直接在内存中构造XmlTextWriter，并用XmlReader进行读取。

使用MemoryStream和XmlTextWriter进行书写XML,需要注意两点：XmlTextWriter.Flush操作和重设MemoryStream.Position = 0。

<% @ Page Language = " C# " %>
<% @ Import Namespace = " System.Xml "   %>
<% @ Import Namespace = " System.IO "   %>
<! DOCTYPE html PUBLIC  " -//W3C//DTD XHTML 1.0 Transitional//EN "   " http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd " >

< script runat = " server " >
   protected   void  Button1_Click( object  sender, EventArgs e)
   ... {
    Response.Clear();
    Response.ContentType = "text/xml";
    MemoryStream msXml = new MemoryStream();
    XmlTextWriter xmlWriter = new XmlTextWriter(msXml, Encoding.UTF8);
    xmlWriter.WriteStartElement("rss");
    xmlWriter.WriteAttributeString("version", "2.0");
    xmlWriter.WriteStartElement("channel");
    xmlWriter.WriteElementString("title", "【孟宪会之精彩世界】");
    xmlWriter.WriteElementString("link", "http://dotnet.aspx.cc/Rss.aspx");
    xmlWriter.WriteElementString("description", "NET开发技术。");
    xmlWriter.WriteElementString("language", "zh-CN");
    xmlWriter.WriteElementString("copyright", "Copyright 1999-2007【孟宪会之精彩世界】");
    xmlWriter.WriteElementString("managingEditor", "amxh[AT]21cn.com");
    xmlWriter.WriteStartElement("image");
    xmlWriter.WriteElementString("title", "【孟宪会之精彩世界】");
    xmlWriter.WriteElementString("width", "144");
    xmlWriter.WriteElementString("height", "35");
    xmlWriter.WriteElementString("link", "http://dotnet.aspx.cc/");
    xmlWriter.WriteElementString("url", "http://dotnet.aspx.cc/Images/LogoRss.gif");
    xmlWriter.WriteEndElement();

    //循环读出数据库内容列表，忽略
    //while (objReader.Read())
    //{
    //  xmlWriter.WriteStartElement("item");
    //  xmlWriter.WriteElementString("title", objReader.GetString(0));
    //  xmlWriter.WriteElementString("description", objReader.GetString(1));
    //  xmlWriter.WriteElementString("link", "http://dotnet.aspx.cc/article/a933b187-06c3-4263-9eec-414a54d9c815/read.aspx");
    //  xmlWriter.WriteElementString("pubDate", objReader.GetDateTime(3).ToString("G"));
    //  xmlWriter.WriteEndElement();
    //}
    //objReader.Close();
    xmlWriter.WriteStartElement("item");
    xmlWriter.WriteElementString("title", "ASP.NET 2.0中直接将Access数据库导入到Excel文件中");
    xmlWriter.WriteElementString("description", "ASP.NET 2.0中直接将Access数据库导入到Excel文件中");
    xmlWriter.WriteElementString("link", "http://dotnet.aspx.cc/article/a933b187-06c3-4263-9eec-414a54d9c815/read.aspx");
    xmlWriter.WriteElementString("pubDate", "Sat, 02 Dec 2006 09:39:58 GMT");
    xmlWriter.WriteEndElement();
    xmlWriter.WriteEndElement();
    xmlWriter.WriteEndElement();
    xmlWriter.Flush();  // 确保书写器更新到Stream中；
    msXml.Position = 0; // 重置流的位置，以便我们可以从头读取     
    XmlReader xmlReader = XmlReader.Create(msXml);
    while (xmlReader.Read())
    ...{
      if (xmlReader.Name == "rss")
      ...{
        Response.Write(xmlReader.ReadOuterXml());
      }
    }
    Response.End();
    msXml.Close();
    xmlWriter.Close();
    xmlReader.Close();
  }
</ script >

< html xmlns = " http://www.w3.org/1999/xhtml " >
< head runat = " server " >
   < title > XmlReader 读取器读取内存流 MemoryStream 的注意事项 </ title >
</ head >
< body >
   < form id = " form1 "  runat = " server " >
     < asp:Button ID = " Button1 "  runat = " server "  OnClick = " Button1_Click "  Text = " 读取数据 "   />
   </ form >
</ body >
</ html >