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。

  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.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>

  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.aspx.cc/Images/LogoRss.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