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">

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("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.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>

<title>XmlReader 读取器读取内存流 MemoryStream 的注意事项</title>

</head>

<body>

<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("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.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