XML DataBinding concept is used to retrieve the data from XML file using XmlDataProvider in XAML language. Windows Presentation Foundation makes it possible to create user interfaces that use data binding wholly in an XML-based markup. When working with XAML we can use the XmlDataProvider object to retrieve XML data and provide it to controls.
Format for Accessing XMLData
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. First, we create a XmlDataProvider that will retrieve data asynchronously from the given address and create the data collection with XPath.
XPath :
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.
- 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.
Source :
We can specify the xml file source address in source attribute.
Example 1:
This sample will help you to get data from external XML file named as BookData.xml and binded with listbox.
BookData.xml
<Book ISBN="0-7356-0562-9" Stock="in">
<Title>XML in Action</Title>
<Summary>XML Web Technology</Summary>
</Book>
<Book ISBN="0-7356-1370-2" Stock="in">
<Title>Programming Microsoft Windows With C#</Title>
<Summary>C# Programming using the .NET Framework</Summary>
</Book>
<Book ISBN="0-7356-1288-9" Stock="out">
<Title>Inside C#</Title>
<Summary>C# Language Programming</Summary>
</Book>
<Book ISBN="0-7356-1377-X" Stock="in">
<Title>Introducing Microsoft .NET</Title>
<Summary>Overview of .NET Technology</Summary>
</Book>
<Book ISBN="0-7356-1448-2" Stock="out">
<Title>Microsoft C# Language Specifications</Title>
<Summary>The C# language definition</Summary>
</Book>
</Books>
Window1.xaml
<StackPanel xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="410" Height="350" Background="White">
<StackPanel.Resources>
<XmlDataProvider x:Key="BookData" Source="bookdata.xml" XPath="Books"/>
<DataTemplate x:Key="BookDataTemplate">
<TextBlock FontSize="12" Foreground="White">
<TextBlock.Text>
<Binding XPath="Summary"/>
</TextBlock.Text>
</TextBlock>
</DataTemplate>
</StackPanel.Resources>
<TextBlock FontSize="18" FontWeight="Bold" Margin="10" HorizontalAlignment="Center">Data From XML</TextBlock>
<ListBox Width="200" Height="300" Background="SteelBlue" ItemsSource="{Binding Source={StaticResource BookData}, XPath=Book}" ItemTemplate="{StaticResource BookDataTemplate}"/>
</StackPanel>
Note :
You can put the Xml file in same location of xaml file. If you have external path means you should specify the path of xml file in source(Ex : Source ="data\bookdata.xml" attribute of XmlDataProvider tag.
Example 2:
This sample will help you to embed directly as an XML data island within the Resources :
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.
<StackPanel xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Background="White">
<StackPanel.Resources>
<XmlDataProvider x:Key="InventoryData" XPath="Inventory/Books">
<x:XData>
<Inventory xmlns="">
<Books>
<Book ISBN="0-7356-0562-9" Stock="in" Number="9">
<Title>XML in Action</Title>
<Summary>XML Web Technology</Summary>
</Book>
<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>
<Book ISBN="0-7356-1288-9" Stock="out" Number="7">
<Title>Inside C#</Title>
<Summary>C# Language Programming</Summary>
</Book>
<Book ISBN="0-7356-1377-X" Stock="in" Number="5">
<Title>Introducing Microsoft .NET</Title>
<Summary>Overview of .NET Technology</Summary>
</Book>
<Book ISBN="0-7356-1448-2" Stock="out" Number="4">
<Title>Microsoft C# Language Specifications</Title>
<Summary>The C# language definition</Summary>
</Book>
</Books>
<CDs>
<CD Stock="in" Number="3">
<Title>Classical Collection</Title>
<Summary>Classical Music</Summary>
</CD>
<CD Stock="out" Number="9">
<Title>Jazz Collection</Title>
<Summary>Jazz Music</Summary>
</CD>
</CDs>
</Inventory>
</x:XData>
</XmlDataProvider>
</StackPanel.Resources>
<TextBlock FontSize="18" FontWeight="Bold" Margin="10" HorizontalAlignment="Center">XML Data Source Sample</TextBlock>
<ListBox Width="400" Height="300" Background="SteelBlue">
<ListBox.ItemsSource>
<Binding Source="{StaticResource InventoryData}" XPath="*[@Stock='out'] *[@Number>=8 or @Number=3]"/>
</ListBox.ItemsSource>
<!--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]}">-->
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock FontSize="12" Foreground="Red"> <TextBlock.Text>
<Binding XPath="Title"/>
</TextBlock.Text>
</TextBlock>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
hi venu,,, its really nice,jus now i started to work in this technology,,, can u tell me how to retrieve the xml attribute on clicking the listview items,,, for eg)
ReplyDelete(employee)
(emp emp_id=1)
(name)...(name)
(emp)
(employee)
i binded this xml file with listview,,,
now on clicking the list items in listview i should display the corresponding attr,,, here emp_id in the text box,,,,,, u can mail me regarding this to,,,,vinoth_sns@yahoo.co.in,,,,thnx and expecting ur reply soon,,,,
cheers,
vinu,,