ASP.NET Tutorial/XML/XMLTextReader

Материал из .Net Framework эксперт
Перейти к: навигация, поиск

Fill XML data into StringBuilder from XmlTextReader

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="ReadXmlEfficient" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <asp:Literal id="XmlText" runat="server"></asp:Literal>
    </div>
    </form>
</body>
</html>
File: Default.aspx.cs
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;
using System.Xml;
public partial class ReadXmlEfficient : System.Web.UI.Page
{
  protected void Page_Load(object sender, EventArgs e)
  {
    string xmlFile = Server.MapPath("Data.xml");
    XmlTextReader reader = new XmlTextReader(xmlFile);
    StringBuilder str = new StringBuilder();
    reader.ReadStartElement("DvdList");
    while (reader.Read())
    {
      if ((reader.Name == "DVD") && (reader.NodeType == XmlNodeType.Element))
      {
        reader.ReadStartElement("DVD");
        str.Append("<ul><b>");
        str.Append(reader.ReadElementString("Title"));
        str.Append("</b><li>");
        str.Append(reader.ReadElementString("Director"));
        str.Append("</li><li>");
        str.Append(String.Format("{0:C}",Decimal.Parse(reader.ReadElementString("Price"))));
        str.Append("</li></ul>");
      }
    }
    reader.Close();
    XmlText.Text = str.ToString();
  }
}
File: Data.xml
<?xml version="1.0"?>
<DvdList>
   <DVD ID="1" Category="Category 1">
      <Title>title 1</Title>
      <Director>directory 2</Director>
      <Price>1</Price>
      <Starring>
         <Star>star 1</Star>
         <Star>star 2</Star>
      </Starring>
   </DVD>
   <DVD ID="2" Category="Category 2">
      <Title>title 2</Title>
      <Director>directory 2</Director>
      <Price>2</Price>
      <Starring>
         <Star>star 3</Star>
         <Star>star 4</Star>
      </Starring>
   </DVD>
</DvdList>


Read xml and build page along with it

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="ReadXML" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
   <title>Loading a DataSet with XML</title>
</head>
<body>
   <form id="form1" runat="server">
      <div id="container">
         <h1>Loading a DataSet with XML</h1>
         Enter the filename or the URL for the XML to be loaded:<br />
         <asp:TextBox ID="txtXML" runat="server" Columns="60"/>
         <asp:Button ID="btnLoad" runat="server" Text="Load XML" OnClick="btnLoad_Click" />
         <asp:Panel ID="panData" runat="server">
         Below you will see a list of <code>GridView</code> controls, one for each of the <code>DataTable</code>s generated from the XML
         <asp:PlaceHolder ID="phData" runat="server" />               
         </asp:Panel>
         <hr />
         <asp:Label ID="labMsg" runat="server" CssClass="error"/> 
      </div>
   </form>
</body>
</html>
File: Default.aspx.cs
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Xml;
public partial class ReadXML : System.Web.UI.Page
{
   protected void Page_Load(object sender, EventArgs e)
   {
      if (!IsPostBack)
      {
         panData.Visible = false;
         txtXML.Text = "Data.xml";
      }
   }
   protected void btnLoad_Click(object sender, EventArgs e)
   {
      panData.Visible = true;
      string path = "";
      labMsg.Text = "";
      try
      {
         DataSet ds1 = new DataSet();
         path = txtXML.Text;         
         if (!path.StartsWith("http", StringComparison.CurrentCultureIgnoreCase))
            path = Server.MapPath(path);
         
         XmlTextReader xtr = new XmlTextReader(path);
         ds1.ReadXml(xtr, XmlReadMode.InferSchema);
         foreach (DataTable table in ds1.Tables)
         {
            Literal caption = new Literal();
            caption.Text = "<h2>Table: " + table.TableName + "</h2>";
            phData.Controls.Add(caption);
            GridView grid = new GridView();
            grid.CellPadding = 3;
            grid.DataSource = table.DefaultView;
            grid.DataBind();
            phData.Controls.Add(grid);
         }
      }
      catch (IOException)
      {
         panData.Visible = false;
         labMsg.Text = txtXML.Text + " not found";
      }
      catch
      {
         panData.Visible = false;
         labMsg.Text = path + " unable to be accessed";
      }
   }
}
File: Data.xml
<?xml version="1.0" ?>
<NavMenu title="GameSystems">
   <MenuItem title="PC" icon="images/icon_4.gif" >
      <Games>
         <Game>
            <name>Game 1</name>
            <price>free</price>
         </Game>
         <Game>
            <name>Game 2</name>
            <price>14.99</price>
         </Game>
      </Games>
   </MenuItem>
   <MenuItem title="Mac" icon="images/icon_3.gif" >
      <Games>
         <Game>
            <name>Game 3</name>
            <price>49.99</price>
         </Game>
      </Games>           
   </MenuItem>
</NavMenu>


Use XMLTextReader to read the data in an XML file (VB.net)

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Xml" %>
<script runat=server>
   sub Page_Load(Sender as Object, e as EventArgs)
      dim reader as XMLTextReader
         
      try
         reader = new XMLTextReader(Server.MapPath("Data.xml"))
         While reader.Read()
            Response.Write("<b>" & reader.Name & "</b> " & _
                reader.Value & "<br>")
         
         End While
      catch ex as Exception
         Response.Write("Error accessing XML file")
      finally
         reader.close
      end try
   end sub
</script>
<html><body>
</body></html>
File: Data.xml
<?xml version="1.0"?>
<bookstore>
  <book genre="asdf">
    <title>asdf</title>
    <author>
      <first-name>asdf</first-name>
      <last-name>asdf</last-name>
    </author>
    <price>asdf</price>
  </book>
  <book genre="asdf">
    <title>asdf</title>
    <author>
      <first-name>asdf</first-name>
      <last-name>asdf</last-name>
    </author>
    <price>asdf</price>
  </book>
  <book genre="asdf">
    <title>asdf</title>
    <author>
      <first-name>asdf</first-name>
      <last-name>asdf</last-name>
    </author>
    <price>asdf</price>
  </book>
</bookstore>