在DotNet里面利用XML

文章作者：佚名录入时间：2006-6-13 来源：不详
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呵呵，有意思，听过一个笑话，说德国一个老头，是个聋子，在如厕时，突然苏联战机空袭，虽然房屋倒塌，可是全家人都没有事情，家里人扒开卫生间的墙壁，发现老头在那儿乐，说：我一拉抽水马桶的绳，屋就倒了。
哈哈哈，我也是这样，刚才我一发这贴子，chinaasp就完了，还以为是我的事情呢，原来是苏联飞机来炸了，呵呵。
如果你喜欢玩xml，那么请跟我来，但在此之前，请深呼一口气，因为我给大家介绍一个长代码，在这个代码中揭示了微软在ASP.NET架构中隐藏的一个ＷＥＢ表单控件，即<asp:xml runat=server/>，我只给代码，不给解释，大家自己下课后去研究吧。
另外，由于是beta1，在这个控件中你使用的xslt里面不能使用<xsl:sort>，当然，亦不能使用那个order-by了，因为它支持的xsl空间是带"1999"的那个，而不是原来的那个。
另外，我从微软得到的回答就是在beta2里面，它将支持<xsl:sort>，到那时，哥哥我将全部转向xml+xsl了，现在为源代码保密问题给弄的非常头疼。
请看下例：
webform2.cs
---------------------------------
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Text;
using System.IO;
using System.Xml;

public class WebForm2 : Page
{
public StringBuilder outputQ;
public StringBuilder outputXml;
public DocumentNavigator nav = null;
public HtmlInputFile XmlFile;

public System.Web.UI.WebControls.Xml MyXml;

public System.Web.UI.WebControls.TextBox TextBox1;
public System.Web.UI.WebControls.TextBox TextBox2;
public System.Web.UI.WebControls.TextBox TextBox3;
public System.Web.UI.WebControls.Button Query;
public System.Web.UI.WebControls.Label FileLabel;

public void On_KeyUp(object sender, System.EventArgs e)
{
Response.Write("Works");
}

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
//
// Evals true first time browser hits the page
//
}
}

public void Query_Click(object sender, System.EventArgs e)
{
HttpPostedFile xmlfile = XmlFile.PostedFile;
XmlDocument doc = new XmlDocument();
MyXml.Document = new XmlDocument();
// TextBox2.Text="";
// TextBox3.Text="";

if (xmlfile.FileName != String.Empty)
{
try
{
FileLabel.Text= xmlfile.FileName;

MyXml.Document.Load(xmlfile.FileName);
outputXml = new StringBuilder();
XmlTextReader reader = new XmlTextReader (xmlfile.FileName);
ShowDocument();
TextBox3.Text = outputXml.ToString();

outputQ = new StringBuilder();
doc.Load(xmlfile.FileName);
DocumentNavigator nav = new DocumentNavigator(doc);
// Perform the query e.g. "descendant::book/price"
XPathQuery(nav, TextBox1.Text);
TextBox2.Text = outputQ.ToString();

}
catch (Exception exp) {
//outputQ.Append("</xmp><font color=\"#FF6600\">"+ exp.Message+"</font><xmp>");
}
finally {}
}
else if (FileLabel.Text != String.Empty)
{
try
{
MyXml.Document.Load(FileLabel.Text);
outputXml = new StringBuilder();
XmlTextReader reader = new XmlTextReader (FileLabel.Text);
ShowDocument();
TextBox3.Text = outputXml.ToString();

ShowDocument();

outputQ = new StringBuilder();
doc.Load(FileLabel.Text);
DocumentNavigator nav = new DocumentNavigator(doc);
// Perform the query e.g. "descendant::book/price"
XPathQuery(nav, TextBox1.Text);
TextBox2.Text = outputQ.ToString();

}
catch (Exception exp) {
outputQ.Append("</xmp><font color=\"#FF6600\">"+ exp.Message+"</font><xmp>");
}
finally {}
}
}

private void XPathQuery(XmlNavigator navigator, String xpathexpr )
{
try
{
// Save context node position
navigator.PushPosition();
navigator.Select (xpathexpr);
FormatXml(navigator);

// Restore context node position
navigator.PopPosition();
}
catch (Exception e)
{
}
}

//***************************** Navigator ************************************
private void FormatXml (XmlNavigator navigator)
{
while (navigator.MoveToNextSelected())
{
switch (navigator.NodeType)
{
case XmlNodeType.ProcessingInstruction:
Format (navigator, "ProcessingInstruction");
break;
case XmlNodeType.DocumentType:
Format (navigator, "DocumentType");
break;
case XmlNodeType.Document:
Format (navigator, "Document");
break;
case XmlNodeType.Comment:
Format (navigator, "Comment");
break;
case XmlNodeType.Element:
Format (navigator, "Element");
break;
case XmlNodeType.Text:
Format (navigator, "Text");
break;
case XmlNodeType.Whitespace:
Format (navigator, "Whitespace");
break;
}
}
outputQ.Append("\r\n");
}

// Format the output
private void Format (XmlNavigator navigator, String NodeType)
{
String value = String.Empty;
String name = String.Empty;

if (navigator.HasChildren)
{
name = navigator.Name;
navigator.MoveToFirstChild();
if (navigator.HasValue)
{
value = navigator.Value;
}
}
else
{
if (navigator.HasValue)
{
value = navigator.Value;
name = navigator.Name;
}
}
outputQ.Append(NodeType + "<" + name + ">" + value);
outputQ.Append("\r\n");
}

// ********************************** XmlReader *****************************
public void ShowDocument ()
{
outputXml = new StringBuilder();
XmlTextReader reader = new XmlTextReader (FileLabel.Text);

while (reader.Read())
{
switch (reader.NodeType)
{
case XmlNodeType.ProcessingInstruction:
Format (reader, "ProcessingInstruction");
break;
case XmlNodeType.DocumentType:
Format (reader, "DocumentType");
break;
case XmlNodeType.Comment:
Format (reader, "Comment");
break;
case XmlNodeType.Element:
Format (reader, "Element");
break;
case XmlNodeType.Text:
Format (reader, "Text");
break;
case XmlNodeType.Whitespace:
break;
}
}
TextBox3.Text = outputXml.ToString();
}

protected void Format(XmlReader reader, String NodeType)
{
// Format the output
for (int i=0; i < reader.Depth; i++)
{
outputXml.Append('\t');
}

outputXml.Append(reader.Prefix + NodeType + "<" + reader.Name + ">" + reader.Value);

// Display the attributes values for the current node
if (reader.HasAttributes)
{
outputXml.Append(" Attributes:");

for (int j=0; j < reader.AttributeCount; j++)
{
outputXml.Append(reader[j]);
}
}
outputXml.Append("\r\n");
}

/// ************************* DOM *********************************
protected void ShowDocument(XmlNode node)
{
if (node != null)
Format (node);

if (node.HasChildNodes)
{
node = node.FirstChild;
while (node != null)
{
ShowDocument(node);
node = node.NextSibling;
}
}
}

// Format the output
private void Format (XmlNode node)
{
if (!node.HasChildNodes)
{
outputXml.Append("\t" + "<" + node.Value + ">");
}

else
{
outputXml.Append("<" + node.Name + ">");
if (XmlNodeType.Element == node.NodeType)
{
XmlNamedNodeMap map = node.Attributes;
foreach (XmlNode attrnode in map)
outputXml.Append(" " + attrnode.Name + "<" + attrnode.Value + "> ");
}
outputXml.Append("\r\n");
}
}
}

下面就是webform2.aspx了
webform2.aspx
-----------------------------------
<%@ Import Namespace="System" %>
<%@ Import Namespace="System.IO" %>
<%@ Assembly Name="System.Xml" %>
<%@ Import Namespace="System.Xml" %>
<%@ Page Language="C#" Inherits="WebForm2" Src="WebForm2.cs" Debug="true" %>

</script>

<TITLE>test</TITLE>
</HEAD>

<BODY >

<div align="left">
<table>
<tr>
<td>XML Document:</td>
<td><input type=file id="XmlFile" runat=server> FileName:</td>
<td><asp:label id="FileLabel" runat="server"></asp:label></td>
</tr>

<tr>
<td>XPath Expression</td>
<td><asp:textbox id=TextBox1 runat="server" Height="20" Width="300" text=".//text()" OnKey_Up="On_KeyUp"></asp:textbox></td>
<td><asp:button type=submit OnClick="Query_Click" runat="server" Height="20" Width="91" text="Query"></asp:button></td>
</tr>
</table>

</br>
<table>
<tr><td>Output from Query</td><td>XML Data</td><tr>
<tr><td>Query Display: <asp:dropdownlist runat="server">
<asp:listitem>Descriptive</asp:listitem>
<asp:listitem>XML</asp:listitem>
</asp:dropdownlist>
</td><tr>
<tr>
<td width="50%" valign="top" align="left"><asp:textbox id=TextBox2 runat="server" Height="400" Width="350" TextMode="MultiLine" Rows="10"></asp:textbox></td>
<td width="50%" valign="top" align="left"><asp:xml id="MyXml" transformsource="test.xsl" runat=server/></asp:xml></td>
</tr>
</table>
</div>

</form>

</BODY>
</HTML>