ASP.NET中的XML表单控件

March 25,2004

导读：介绍了有关ASP.NET中XML控件的使用,有个小BUG:在WEBFORM.ASPX中出现的XML控件,其中的transformsource属性设定了样式表文件路径,可是在文章出处没有找到这个XSL文件.:( 自己解决吧.
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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>，就可以全部转向xml+xsl了，而不用再为源代码保密问题头疼了。
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("rn");
}

// 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("rn");
}

// ********************************** 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("rn");
}

/// ************************* 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("rn");
      }
}
}

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" %>

<HTML><HEAD>

  <script runat="server" language="C#">
// Put page script here
      public void On_KeyUp(object sender, System.EventArgs e)
{
      Response.Write("Works");
}

  </script>


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

<BODY >

<form method="post" action="WebForm2.aspx" runat="server" enctype="multipart/form-data">

<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>

<td><asp:textbox id=TextBox3 runat="server" Height="1" Width="5" TextMode="MultiLine" Rows="110"></asp:textbox></td>

</form>

</BODY>
</HTML>