bind textblock to current listbox item in pure xaml - wpf

Question

i have some data saved in a xml file.
Those will be displayed in a listbox.
Now, when i change the listbox Selectedindex, i would like to update the other information in the textblock based on the selectedindex.
is there any way to do this in pure xaml?
if not, how would i bind the Textblock to the selecteditem in the listbox ?
EDIT:
How would i navigate through the Data without using the listbox? i mean using a button to move to next item and other button to move backward..!!
any help is really appreciated..
<Window x:Class="WpfSingleInstance.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Grid>
<StackPanel
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Background="Cornsilk">
<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>
</Books>
</Inventory>
</x:XData>
</XmlDataProvider>
</StackPanel.Resources>
<TextBlock FontSize="18" FontWeight="Bold" Margin="10"
HorizontalAlignment="Center">XML Data Source Sample</TextBlock>
<ListBox
Width="265" Height="98" x:Name="lbox" Background="Honeydew" IsSynchronizedWithCurrentItem="True">
<ListBox.ItemsSource>
<Binding Source="{StaticResource InventoryData}"
XPath="*[#Stock='out'] | *[#Number>=8 or #Number=3]"/>
</ListBox.ItemsSource>
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock FontSize="12" Foreground="Red">
<TextBlock.Text>
<Binding XPath="Title"/>
</TextBlock.Text>
</TextBlock>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<StackPanel DataContext="{StaticResource InventoryData}">
<TextBlock Text="{Binding XPath=Book/Title}"/>
<TextBox Margin="5,31,98,10" x:Name="textBoxMainDetail" Text="{Binding XPath=Book/Summary}" />
</StackPanel>
</StackPanel>
</Grid>

Answer 1

You could bind like this:
<TextBox Text="{Binding ElementName=lbox, Path=SelectedItem[Title].InnerText}" />
SelectedItem is an XmlElement.
EDIT: Here is a bit of sample code how to access the data of the XmlDataProvider in code behind and apply it as DataContent of a TextBox.
Change the TextBox.Text binding like this:
<TextBox x:Name="textBoxMainDetail" Text="{Binding Path=[Title].InnerText}" />
In code behind get the XML data from the XmlDataProvider and set the DataContext of the TextBox:
XmlDataProvider dataProvider = (XmlDataProvider)stackPanel.Resources["InventoryData"];
XmlElement books = (XmlElement)dataProvider.Document.SelectNodes(dataProvider.XPath)[0];
// set DataContext to an item from the child node collection
textBoxMainDetail.DataContext = books.ChildNodes[0];
Note that the StackPanel with the XmlDataProvider in its resource dictionary has now got a name. If this code shall run during application initialization (e.g. in Window constructor), the XmlDataProvider.IsAsynchronous property must be set to false.
You should now be able to change the DataContext to another indexed item of the books collection in a button click handler.

Answer 2

You need to set the SelectedValuePath as the 'Title' for your listbox. Then simply bind the your textBlock to the selectedValue of your listbox using elementName like this -
<ListBox Width="265" Height="98" x:Name="lbox" Background="Honeydew"
IsSynchronizedWithCurrentItem="True" SelectedValuePath="Title">
</ListBox>
<StackPanel DataContext="{StaticResource InventoryData}">
<TextBlock Text="{Binding Path=SelectedValue, ElementName=lbox}"/>
<TextBox Margin="5,31,98,10" x:Name="textBoxMainDetail" Text="{Binding XPath=Book/Summary}" />
</StackPanel>
</StackPanel>