XPathBinder Class

Reference

Definition

Namespace:: System.Web.UI

Assembly:: System.Web.dll

Important

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Provides support for rapid application development (RAD) designers to parse data-binding expressions that use XPath expressions. This class cannot be inherited.

public ref class XPathBinder sealed

public sealed class XPathBinder

type XPathBinder = class

Public NotInheritable Class XPathBinder

Inheritance: Object
XPathBinder

Examples

The following code example demonstrates how to use an XmlDataSource control with a templated Repeater control to display XML data. This example has two parts:

A Web Forms page that displays XML data.
An XML file that contains the data.

The first part of the example shows a Web Forms page that displays XML data accessed through an XmlDataSource control. A Repeater control uses simplified Eval(Object, String) method syntax to bind to data items within the XML document that the XmlDataSource represents. It uses the Select(Object, String) method to retrieve an IEnumerable list and assign it as a late-bound DataSource property for the Repeater control.

<%@ Page Language="C#" %>
<!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 runat="server">
    <title>Order</title>
</head>
<body>
    <form id="form1" runat="server">
      <asp:XmlDataSource
        runat="server"
        id="XmlDataSource1"
        XPath="orders/order"
        DataFile="order.xml" />

      <asp:Repeater ID="Repeater1"
        runat="server"
        DataSourceID="XmlDataSource1">
        <ItemTemplate>
            <h2>Order</h2>
            <table>
              <tr>
                <td>Customer</td>
                <td><%#XPath("customer/@id")%></td>
                <td><%#XPath("customername/firstn")%></td>
                <td><%#XPath("customername/lastn")%></td>
              </tr>
              <tr>
                <td>Ship To</td>
                <td><%#XPath("shipaddress/address1")%></font></td>
                <td><%#XPath("shipaddress/city")%></td>
                <td><%#XPath("shipaddress/state")%>,
                    <%#XPath("shipaddress/zip")%></td>
              </tr>
            </table>
            <h3>Order Summary</h3>
            <asp:Repeater ID="Repeater2"
                 DataSource='<%#XPathSelect("summary/item")%>'
                 runat="server">
                <ItemTemplate>
                     <b><%#XPath("@dept")%></b> -
                         <%#XPath(".")%><br />
                </ItemTemplate>
            </asp:Repeater>
            <hr />
        </ItemTemplate>
    </asp:Repeater>

  </form>
  </body>
</html>

<%@ Page Language="VB" %>
<!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 runat="server">
    <title>Order</title>
</head>
<body> 
    <form id="form1" runat="server">
      <asp:XmlDataSource
        runat="server"
        id="XmlDataSource1"
        XPath="orders/order"
        DataFile="order.xml" />

      <asp:Repeater ID="Repeater1"
        runat="server"
        DataSourceID="XmlDataSource1">
        <ItemTemplate>
            <h2>Order</h2>
            <table>
              <tr>
                <td>Customer</td>
                <td><%#XPath("customer/@id")%></td>
                <td><%#XPath("customername/firstn")%></td>
                <td><%#XPath("customername/lastn")%></td>
              </tr>
              <tr>
                <td>Ship To</td>
                <td><%#XPath("shipaddress/address1")%></font></td>
                <td><%#XPath("shipaddress/city")%></td>
                <td><%#XPath("shipaddress/state")%>,
                    <%#XPath("shipaddress/zip")%></td>
              </tr>
            </table>
            <h3>Order Summary</h3>
            <asp:Repeater ID="Repeater2"
                 DataSource='<%#XPathSelect("summary/item")%>'
                 runat="server">
                <ItemTemplate>
                     <b><%#XPath("@dept")%></b> -
                         <%#XPath(".")%><br />
                </ItemTemplate>
            </asp:Repeater>
            <hr />
        </ItemTemplate>
    </asp:Repeater>

  </form>
  </body>
</html>

The second example provides the XML file, Order.xml, that is used as the source of the data displayed in the Web Forms page defined above.

<?xml version="1.0" encoding="iso-8859-1"?>  
  <orders>  
    <order>  
      <customer id="12345" />  
      <customername>  
        <firstn>John</firstn>  
        <lastn>Doe</lastn>  
      </customername>  
      <transaction id="12345" />  
      <shipaddress>  
        <address1>1234 Tenth Avenue</address1>  
        <city>Bellevue</city>  
        <state>Washington</state>  
        <zip>98001</zip>  
      </shipaddress>  
      <summary>  
        <item dept="tools">screwdriver</item>  
        <item dept="tools">hammer</item>  
        <item dept="plumbing">fixture</item>  
      </summary>  
    </order>  
 </orders>

Remarks

You can use the overloaded Eval method of this class to bind to the result of an XPath expression executed against an object that implements the IXPathNavigable interface, such as an XmlNode. You can use the Select method to retrieve the results of an XPath expression executed against an IXPathNavigable object as an IEnumerable list of nodes. This list of nodes can be enumerated directly or assigned to the DataSource property of a list control, such as a Repeater or DataList.

You can use a simplified version of data-binding syntax when using the XPathBinder methods declaratively. Instead of calling XPathBinder.Eval(Container.DataItem, xpath) you can use XPath(xpath). Similarly, instead of calling XPathBinder.Select(Container.DataItem,xpath), you can use XPathSelect(xpath) to retrieve an IEnumerable set of nodes. When using this simplified syntax, the Eval and Select methods assume a default Container.DataItem context object.

For more information about data binding to ASP.NET server controls, see Data-Binding Expression Syntax.

Methods

Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
Eval(Object, String)	Evaluates XPath data-binding expressions at run time.
Eval(Object, String, IXmlNamespaceResolver)	Evaluates XPath data-binding expressions at run time and formats the result as text to be displayed in the requesting browser, using the IXmlNamespaceResolver object specified to resolve namespace prefixes in the XPath expression.
Eval(Object, String, String)	Evaluates XPath data-binding expressions at run time and formats the result as text to be displayed in the requesting browser.
Eval(Object, String, String, IXmlNamespaceResolver)	Evaluates XPath data-binding expressions at run time and formats the result as text to be displayed in the requesting browser, using the IXmlNamespaceResolver object specified to resolve namespace prefixes in the XPath expression.
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
Select(Object, String)	Uses an XPath data-binding expression at run time to return a list of nodes.
Select(Object, String, IXmlNamespaceResolver)	Uses an XPath data-binding expression at run time to return a list of nodes, using the IXmlNamespaceResolver object specified to resolve namespace prefixes in the XPath expression.
ToString()	Returns a string that represents the current object. (Inherited from Object)

Applies to