XmlReader 读取器读取内存流

ChinaItLab

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2006-12-21

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    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。

  C#

  <%@ 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.chinaitlab.com/UploadFiles_6597/200612/20061221105058663.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>
  VB.NET

  Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)
   Response.Clear
   Response.ContentType = "text/xml"
   Dim msXml As MemoryStream = New MemoryStream
   Dim xmlWriter As XmlTextWriter = 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.chinaitlab.com/UploadFiles_6597/200612/20061221105058663.gif")
   xmlWriter.WriteEndElement
   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
   msXml.Position = 0
   Dim xmlReader As XmlReader = XmlReader.Create(msXml)
   While xmlReader.Read
   If xmlReader.Name = "rss" Then
   Response.Write(xmlReader.ReadOuterXml)
   End If
   End While
   Response.End
   msXml.Close
   xmlWriter.Close
   xmlReader.Close
  End Sub

【责编:Peng】