ASP.Net/XML/XPath

Содержание

1 Finding a Particular Node in an XML Document?
2 Finding a Particular Node in an XML Document (VB)
3 Use XML Path to locate Node and edit its value
4 Use XPathNavigator to create attribute
5 Use XPath to read XML document
6 Using the XPathNavigator for Navigating Xml Documents
7 XPathNavigator Selection Example

Finding a Particular Node in an XML Document?

   <source lang="csharp">

<%@ Page language="c#" AutoEventWireup="true" %> <%@ Import Namespace="System.Data" %> <script language="C#" runat="server"> protected System.Xml.XmlDocument xmlSource = new System.Xml.XmlDocument(); private void LoadButton_Click(object sender, System.EventArgs e) {

   System.IO.Stream xmlDocStream = GetXmlDoc(XmlSourceTextBox.Text);
   if(xmlDocStream!=null) {
   xmlSource.Load(xmlDocStream);
   ResultText.Text=xmlSource.InnerXml;
   } 
   else 
   {
     ResultText.Text="Could not resolve the XML document.";
   }

}

public static System.IO.Stream GetXmlDoc(string xmlsource) {

   System.IO.Stream stream=null;
   if(xmlsource.StartsWith("<?xml") || xmlsource.StartsWith("<schema") ) 
   {
   stream = new System.IO.MemoryStream(System.Text.ASCIIEncoding.ASCII.GetBytes(xmlsource));
   } 
   else 
   {
   try 
   {
     System.Uri xmluri = new System.Uri(xmlsource);          
     if(xmluri.IsFile) {
         stream = new System.IO.FileStream(xmlsource, System.IO.FileMode.Open);
     } else {
         System.Net.HttpWebRequest request =  (System.Net.HttpWebRequest) System.Net.WebRequest.Create(xmluri);
         System.Net.WebResponse response = request.GetResponse();      
         stream = response.GetResponseStream();
     }
   }
   catch(Exception e) 
   {
   }
   }
   return stream;

} private void QueryButton_Click(object sender, System.EventArgs e) {

   System.Text.StringBuilder s = new System.Text.StringBuilder();
   if(xmlSource==null || xmlSource.InnerText=="") xmlSource.LoadXml(ResultText.Text);
   try 
   {
   System.Xml.XmlNodeList nl = xmlSource.SelectNodes(XPathText.Text);
   int counter=1;
   foreach(System.Xml.XmlNode node in nl) 
   {
     s.Append(counter + "]" + node.InnerText + System.Environment.NewLine);
     counter++;
   }
   QueryResult.Text=s.ToString();
   }
   catch(Exception selectNodesError) 
   {
   QueryResult.Text=selectNodesError.ToString();
   }

} </script> <HTML>

 <HEAD>
   <title>Finding a Particular Node in an XML Document</title>
 </HEAD>
 <body>
   <form id="Form1" method="post" runat="server">
     <asp:textbox id="XmlSourceTextBox" runat="server" Width="379px" Height="162px" TextMode="MultiLine"></asp:textbox>

     <asp:button id="LoadButton" runat="server" Text="Load XML Document" OnClick="LoadButton_Click"></asp:button>

     <asp:TextBox id="ResultText" runat="server" Width="379px" Height="194px" TextMode="MultiLine"></asp:TextBox>

     <asp:Button id="QueryButton" runat="server" Text="Query" OnClick="QueryButton_Click"></asp:Button>

     <asp:TextBox id="XPathText" runat="server" Width="379px"></asp:TextBox>

     <asp:TextBox id="QueryResult" runat="server" TextMode="MultiLine" Height="229px" Width="379"></asp:TextBox>
   </form>
 </body>

</HTML>

</source>

Finding a Particular Node in an XML Document (VB)

   <source lang="csharp">

<%@ Page language="vb" AutoEventWireup="true" %> <%@ Import Namespace="System.Data" %> <script language="vb" runat="server"> Protected xmlSource As New System.Xml.XmlDocument()

Private Sub LoadButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)

   Dim xmlDocStream As System.IO.Stream = GetXmlDoc(XmlSourceTextBox.Text)
   If Not (xmlDocStream Is Nothing) Then
   xmlSource.Load(xmlDocStream)
   ResultText.Text = xmlSource.InnerXml
   Else
   ResultText.Text = "Could not resolve the XML document."
   End If

End Sub Public Shared Function GetXmlDoc(ByVal xmlsource As String) As System.IO.Stream

   Dim stream As System.IO.Stream = Nothing
   If xmlsource.StartsWith("<?xml") Or xmlsource.StartsWith("<schema") Then
   stream = New System.IO.MemoryStream(System.Text.ASCIIEncoding.ASCII.GetBytes(xmlsource))
   Else
   Try
     Dim xmluri As New System.Uri(xmlsource)
     If xmluri.IsFile Then
         stream = New System.IO.FileStream(xmlsource, System.IO.FileMode.Open)
     Else
         Dim request As System.Net.HttpWebRequest = CType(System.Net.WebRequest.Create(xmluri), System.Net.HttpWebRequest)
         Dim response As System.Net.WebResponse = request.GetResponse()
         stream = response.GetResponseStream()
     End If
   Catch e As Exception
   End Try "not a valid uri
   End If
   Return stream

End Function Private Sub QueryButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)

   Dim s as new System.Text.StringBuilder()
   
   If xmlSource Is Nothing Or xmlSource.InnerText = "" Then
   xmlSource.LoadXml(ResultText.Text)
   End If
   Try
   Dim nl As System.Xml.XmlNodeList = xmlSource.SelectNodes(XPathText.Text)
   Dim counter As Integer = 1
   Dim node As System.Xml.XmlNode
   For Each node In nl
     s.Append(Convert.ToString(counter) + "]" + node.InnerText + System.Environment.NewLine)
         
     counter += 1
   Next node
   QueryResult.Text=s.ToString()
   Catch selectNodesError As Exception
     QueryResult.Text = selectNodesError.ToString()
   End Try

End Sub </script> <HTML>

 <HEAD>
   <title>Finding a Particular Node in an XML Document</title>
 </HEAD>
 <body>
   <form id="Form1" method="post" runat="server">
     <asp:textbox id="XmlSourceTextBox" runat="server" Width="379px" Height="162px" TextMode="MultiLine"></asp:textbox>

     <asp:button id="LoadButton" runat="server" Text="Load XML Document" OnClick="LoadButton_Click"></asp:button>

     <asp:TextBox id="ResultText" runat="server" Width="379px" Height="194px" TextMode="MultiLine"></asp:TextBox>

     <asp:Button id="QueryButton" runat="server" Text="Query" OnClick="QueryButton_Click"></asp:Button>

     <asp:TextBox id="XPathText" runat="server" Width="379px"></asp:TextBox>

     <asp:TextBox id="QueryResult" runat="server" TextMode="MultiLine" Height="229px" Width="379"></asp:TextBox>
   </form>
 </body>

</HTML>

</source>

Use XML Path to locate Node and edit its value

   <source lang="csharp">

<%-- Code Revised from

Professional ASP.NET 2.0 XML (Programmer to Programmer) (Paperback) by Thiru Thangarathinam

Publisher: Wrox (January 18, 2006)
Language: English
ISBN: 0764596772

--%>

<%@ Page Language="C#" %> <%@ Import Namespace="System.Xml" %> <%@ Import Namespace="System.Xml.XPath" %> <script runat="server">

   void Page_Load(object sender, EventArgs e)
   {
       //Set the ContentType to XML to write XML values
       Response.ContentType = "text/xml";
       string xmlPath = MapPath("MyBooks.xml");
       XmlDocument document = new XmlDocument();        
       document.Load(xmlPath);
       XPathNavigator navigator = document.CreateNavigator();
       int count = navigator.Select("/bookstore/book").Count;
       //Navigate to the right nodes
       navigator.MoveToChild("bookstore", "");
       navigator.MoveToChild("book", "");
       //Loop through all the book nodes
       for(int i = 0; i < count; i++)
       {                   
           navigator.MoveToChild("price", "");
           double discount = navigator.ValueAsDouble +1;            
           navigator.CreateAttribute("", "discount", "", discount.ToString());
           //Move to the parent book element
           navigator.MoveToParent();
           //Move to the next sibling book element
           navigator.MoveToNext();            
       }
       navigator.MoveToRoot();
       Response.Write (navigator.OuterXml);
   }

</script>

      </source>

Use XPathNavigator to create attribute

   <source lang="csharp">

<%-- Code Revised from

Professional ASP.NET 2.0 XML (Programmer to Programmer) (Paperback) by Thiru Thangarathinam

Publisher: Wrox (January 18, 2006)
Language: English
ISBN: 0764596772

--%>

<%@ Page Language="C#" %> <%@ Import Namespace="System.Xml" %> <%@ Import Namespace="System.Xml.XPath" %> <script runat="server">

   void Page_Load(object sender, EventArgs e)
   {
       //Set the ContentType to XML to write XML values
       Response.ContentType = "text/xml";
       string xmlPath = MapPath("MyBooks.xml");
       XmlDocument document = new XmlDocument();        
       document.Load(xmlPath);
       XPathNavigator navigator = document.CreateNavigator();
       int count = navigator.Select("/bookstore/book").Count;
       //Navigate to the right nodes
       navigator.MoveToChild("bookstore", "");
       navigator.MoveToChild("book", "");
       //Loop through all the book nodes
       for(int i = 0; i < count; i++)
       {                   
           navigator.MoveToChild("price", "");
           double discount = navigator.ValueAsDouble +1;            
           navigator.CreateAttribute("", "discount", "", discount.ToString());
           //Move to the parent book element
           navigator.MoveToParent();
           //Move to the next sibling book element
           navigator.MoveToNext();            
       }
       navigator.MoveToRoot();
       Response.Write (navigator.OuterXml);
   }

</script>

      </source>

Use XPath to read XML document

   <source lang="csharp">

<%-- Code Revised from

Professional ASP.NET 2.0 XML (Programmer to Programmer) (Paperback) by Thiru Thangarathinam

Publisher: Wrox (January 18, 2006)
Language: English
ISBN: 0764596772

--%>

<%@ Page Language="C#" %> <%@ Import Namespace="System.Xml" %> <script runat="server">

   void Page_Load(object sender, EventArgs e)
   {
       if (!Page.IsPostBack)
       {            
           ddlExpressions.Items.Add("//book/title");
           ddlExpressions.Items.Add("//book[@genre="novel"]/title");
           ddlExpressions.Items.Add("//book/author/first-name");
           ddlExpressions.Items.Add("//book[@genre="philosophy"]/title");
           ddlExpressions.Items.Add("//book/price");
           ddlExpressions.Items.Add("//book[3]/title");
           ddlExpressions.SelectedIndex = 0;
           UpdateDisplay();
       }
   }
   void ddlExpressions_SelectedIndexChanged(object sender, EventArgs e)
   {
       UpdateDisplay();
   }
   void UpdateDisplay()
   {
       lstOutput.Items.Clear();
       string xmlPath = MapPath("MyBooks.xml");
       XmlDocument doc = new XmlDocument();
       doc.Load(xmlPath);
       XmlNodeList nodeList = doc.DocumentElement.SelectNodes(ddlExpressions.SelectedItem.Text);
       foreach (XmlNode child in nodeList)
       {
           lstOutput.Items.Add("Node Name:" + child.Name);
           lstOutput.Items.Add("Node Value:" + child.FirstChild.Value);
       }
   }

</script> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server">

   <title>XPath Example</title>

</head> <body>

   <form id="form1" runat="server">

       Select the XPath Expression:
       <asp:DropDownList ID="ddlExpressions" AutoPostBack="true" runat="server" Width="410px" OnSelectedIndexChanged="ddlExpressions_SelectedIndexChanged">
       </asp:DropDownList>    
       

       

       <asp:ListBox ID="lstOutput" runat="server" Width="587px" Height="168px"></asp:ListBox>

   </form>

</body> </html>

<%-- <?xml version="1.0"?> <bookstore>

 <book genre="autobiography">
   <title>The Autobiography</title>
   <author>
     <first-name>A</first-name>
     <last-name>B</last-name>
   </author>
   <price>999</price>
 </book>
 <book genre="novel">
   <title>The Man</title>
   <author>
     <first-name>C</first-name>
     <last-name>D</last-name>
   </author>
   <price>8888</price>
 </book>

</bookstore>

--%>

      </source>

Using the XPathNavigator for Navigating Xml Documents

   <source lang="csharp">

<%@ Import Namespace="System" %> <%@ Import Namespace="System.Xml" %> <%@ Import Namespace="System.Xml.XPath" %> <%@ Page Language="C#" %> <script runat="server">

   private void Page_Load(Object Source, EventArgs E)
   {
       StringBuilder sb = new StringBuilder();
       String space2 = "  ";
       String space3 = "   ";
   
       XmlDocument _XmlDoc = new XmlDocument();
       _XmlDoc.Load(Server.MapPath("Data.xml"));
   
       XPathNavigator _Nav;
       _Nav = _XmlDoc.CreateNavigator();
   
       _Nav.MoveToRoot();
       sb.Append("Root: ");
       sb.Append("name=" + _Nav.Name + ", type=" + _Nav.NodeType.ToString());
       sb.Append("

");
       
       _Nav.MoveToFirstChild();
       sb.Append("name=" + _Nav.Name + ", type=" + _Nav.NodeType.ToString());
       sb.Append("
");
       
       _Nav.MoveToFirstChild();
       do 
       {
           sb.Append(space2);
           sb.Append("name=" + _Nav.Name + ", type=" + _Nav.NodeType.ToString());
           sb.Append("
");
       
           _Nav.MoveToFirstAttribute();
           sb.Append(space2);
           sb.Append("Attribute: " + _Nav.Name + "=" + _Nav.Value);
           sb.Append("
");
       
           _Nav.MoveToParent();
       
           _Nav.MoveToFirstChild();
           do
           {
               sb.Append(space3);
               sb.Append("name=" + _Nav.Name + ", type=" + _Nav.NodeType.ToString() + ", value=" + _Nav.Value);
               sb.Append("
");
           }while(_Nav.MoveToNext());
       
           _Nav.MoveToParent();
        }while(_Nav.MoveToNext());
       
       OutputLiteral.Text = sb.ToString();
   }

</script> <html> <head> <title>Using the XPathNavigator for Navigating Xml Documents</title> </head> <body>

   <form runat="server">
       
       <asp:Literal id="OutputLiteral" runat="server"></asp:Literal>
   </form>

</body> </html> File: Data.xml <?xml version="1.0" encoding="utf-8" ?> <users>

 <user role="admin">
   <username>jsmith</username>
   <password>john</password>
 </user>
 <user role="operator">
   <username>tcruise</username>
   <password>tom</password>
 </user>

</users>

</source>

XPathNavigator Selection Example

   <source lang="csharp">

<%-- Code Revised from

Professional ASP.NET 2.0 XML (Programmer to Programmer) (Paperback) by Thiru Thangarathinam

Publisher: Wrox (January 18, 2006)
Language: English
ISBN: 0764596772

--%>

<%@ Page Language="C#" %> <%@ Import Namespace="System.Xml" %> <script runat="server">

   void Page_Load(object sender, EventArgs e)
   {
       if (!Page.IsPostBack)
       {            
           ddlExpressions.Items.Add("//book/title");
           ddlExpressions.Items.Add("//book[@genre="novel"]/title");
           ddlExpressions.Items.Add("//book/author/first-name");
           ddlExpressions.Items.Add("//book[@genre="philosophy"]/title");
           ddlExpressions.Items.Add("//book/price");
           ddlExpressions.Items.Add("//book[3]/title");
           ddlExpressions.SelectedIndex = 0;
           UpdateDisplay();
       }
   }
   void ddlExpressions_SelectedIndexChanged(object sender, EventArgs e)
   {
       UpdateDisplay();
   }
   void UpdateDisplay()
   {
       lstOutput.Items.Clear();
       string xmlPath = MapPath("MyBooks.xml");
       XmlDocument doc = new XmlDocument();
       doc.Load(xmlPath);
       XmlNodeList nodeList = doc.DocumentElement.SelectNodes(ddlExpressions.SelectedItem.Text);
       foreach (XmlNode child in nodeList)
       {
           lstOutput.Items.Add("Node Name:" + child.Name);
           lstOutput.Items.Add("Node Value:" + child.FirstChild.Value);
       }
   }

</script> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server">

   <title>XPath Example</title>

</head> <body>

   <form id="form1" runat="server">

       Select the XPath Expression:
       <asp:DropDownList ID="ddlExpressions" AutoPostBack="true" runat="server" Width="410px" OnSelectedIndexChanged="ddlExpressions_SelectedIndexChanged">
       </asp:DropDownList>    
       

       

       <asp:ListBox ID="lstOutput" runat="server" Width="587px" Height="168px"></asp:ListBox>

   </form>

</body> </html>

<%-- <?xml version="1.0"?> <bookstore>

 <book genre="autobiography">
   <title>The Autobiography</title>
   <author>
     <first-name>A</first-name>
     <last-name>B</last-name>
   </author>
   <price>999</price>
 </book>
 <book genre="novel">
   <title>The Man</title>
   <author>
     <first-name>C</first-name>
     <last-name>D</last-name>
   </author>
   <price>8888</price>
 </book>

</bookstore>

--%>

      </source>

ASP.Net/XML/XPath

Содержание

Finding a Particular Node in an XML Document?

Finding a Particular Node in an XML Document (VB)

Use XML Path to locate Node and edit its value

Use XPathNavigator to create attribute

Use XPath to read XML document

Using the XPathNavigator for Navigating Xml Documents

XPathNavigator Selection Example

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