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XmlDataProvider Class

Enables declarative access to XML data for data binding.

Namespace:  System.Windows.Data
Assembly:  PresentationFramework (in PresentationFramework.dll)

[LocalizabilityAttribute(LocalizationCategory.None, Readability = Readability.Unreadable)]
public class XmlDataProvider : DataSourceProvider, 

Security noteSecurity Note:

In a partial-trust sandbox, XmlDataProvider fails when it does not have permissions to access the given data. For more information about partial trust security, see Windows Presentation Foundation Partial Trust Security.

XmlDataProvider exposes the following ways to access XML data.

  • You can embed inline XML data using the XmlDataProvider class.

  • You can set the Source property to the Uri of an XML data file.

  • You can set the Document property to an XmlDocument.

XmlDataProvider performs a full refresh of all bindings when a XmlDocument.NodeChanged event occurs. There are no optimizations for specific nodes.

The XmlDataProvider.IsAsynchronous property is set to true by default, which means that the XmlDataProvider retrieves data and produces the collection of XML nodes asynchronously by default.

This example shows how to bind to XML data using an XmlDataProvider.

With an XmlDataProvider, the underlying data that can be accessed through data binding in your application can be any tree of XML nodes. In other words, an XmlDataProvider provides a convenient way to use any tree of XML nodes as a binding source.

In the following example, the data is embedded directly as an XML data island within the Resources section. An XML data island must be wrapped in <x:XData> tags and always have a single root node, which is Inventory in this example.


The root node of the XML data has an xmlns attribute that sets the XML namespace to an empty string. This is a requirement for applying XPath queries to a data island that is inline within the XAML page. In this inline case, the XAML, and thus the data island, inherits the System.Windows namespace. Because of this, you need to set the namespace blank to keep XPath queries from being qualified by the System.Windows namespace, which would misdirect the queries.


    <XmlDataProvider x:Key="InventoryData" XPath="Inventory/Books">
        <Inventory xmlns="">
            <Book ISBN="0-7356-0562-9" Stock="in" Number="9">
              <Title>XML in Action</Title>
              <Summary>XML Web Technology</Summary>
            <Book ISBN="0-7356-1370-2" Stock="in" Number="8">
              <Title>Programming Microsoft Windows With C#</Title>
              <Summary>C# Programming using the .NET Framework</Summary>
            <Book ISBN="0-7356-1288-9" Stock="out" Number="7">
              <Title>Inside C#</Title>
              <Summary>C# Language Programming</Summary>
            <Book ISBN="0-7356-1377-X" Stock="in" Number="5">
              <Title>Introducing Microsoft .NET</Title>
              <Summary>Overview of .NET Technology</Summary>
            <Book ISBN="0-7356-1448-2" Stock="out" Number="4">
              <Title>Microsoft C# Language Specifications</Title>
              <Summary>The C# language definition</Summary>
            <CD Stock="in" Number="3">
              <Title>Classical Collection</Title>
              <Summary>Classical Music</Summary>
            <CD Stock="out" Number="9">
              <Title>Jazz Collection</Title>
              <Summary>Jazz Music</Summary>

  <TextBlock FontSize="18" FontWeight="Bold" Margin="10"
    HorizontalAlignment="Center">XML Data Source Sample</TextBlock>
    Width="400" Height="300" Background="Honeydew">
      <Binding Source="{StaticResource InventoryData}"
               XPath="*[@Stock='out'] | *[@Number>=8 or @Number=3]"/>

    <!--Alternatively, you can do the following. -->
    <!--<ListBox Width="400" Height="300" Background="Honeydew"
      ItemsSource="{Binding Source={StaticResource InventoryData},
      XPath=*[@Stock\=\'out\'] | *[@Number>\=8 or @Number\=3]}">-->

        <TextBlock FontSize="12" Foreground="Red">
            <Binding XPath="Title"/>

As shown in this example, to create the same binding declaration in attribute syntax you must escape the special characters properly. For more information, see XML Character Entities and XAML.

The ListBox will show the following items when this example is run. These are the Titles of all of the elements under Books with either a Stock value of "out" or a Number value of 3 or greater than or equals to 8. Notice that no CD items are returned because the XPath value set on the XmlDataProvider indicates that only the Books elements should be exposed (essentially setting a filter).

XPath Example

In this example, the book titles are displayed because the XPath of the TextBlock binding in the DataTemplate is set to "Title". If you want to display the value of an attribute, such as the ISBN, you would set that XPath value to "@ISBN".

The XPath properties in WPF are handled by the XmlNode.SelectNodes method. You can modify the XPath queries to get different results. Here are some examples for the XPath query on the bound ListBox from the previous example:

  • XPath="Book[1]" will return the first book element ("XML in Action"). Note that XPath indexes are based on 1, not 0.

  • XPath="Book[@*]" will return all book elements with any attributes.

  • XPath="Book[last()-1]" will return the second to last book element ("Introducing Microsoft .NET").

  • XPath="*[position()>3]" will return all of the book elements except for the first 3.

When you run an XPath query, it returns an XmlNode or a list of XmlNodes. XmlNode is a common language runtime (CLR) object, which means you can use the Path property to bind to the common language runtime (CLR) properties. Consider the previous example again. If the rest of the example stays the same and you change the TextBlock binding to the following, you will see the names of the returned XmlNodes in the ListBox. In this case, the name of all the returned nodes is "Book".

<TextBlock FontSize="12" Foreground="Red">
    <Binding Path="Name"/>

For the complete code sample, see Binding to XML Data Sample.

In some applications, embedding the XML as a data island within the source of the XAML page can be inconvenient because the exact content of the data must be known at compile time. Therefore, obtaining the data from an external XML file is also supported, as in the following example:

<XmlDataProvider x:Key="BookData" Source="data\bookdata.xml" XPath="Books"/>

For the complete code sample, see XMLDataProvider with Embedded Data File Sample.

If the XML data resides in a remote XML file, you would define access to the data by assigning an appropriate URL to the Source attribute as follows:

<XmlDataProvider x:Key="BookData" Source="http://MyUrl" XPath="Books"/>

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0