TreeView uses SelectedValuePath property to provide a SelectedValue for the SelectedItem.


   
   

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="TreeViewSelectedValue">
  <FrameworkElement.Resources>
    <XmlDataProvider x:Key="myCourseData" XPath="/CourseData">
      <x:XData>
        <CourseData xmlns="">
          <CourseInfo>
            <CourseName>A</CourseName>
            <CourseWorkDay>Monday</CourseWorkDay>
            <CourseWorkDay>Tuesday</CourseWorkDay>
            <CourseWorkDay>Wednesday</CourseWorkDay>
            <CourseWorkDay>Thrusday</CourseWorkDay>
            <CourseWorkDay>Friday</CourseWorkDay>
            <CourseStartTime>8:00am</CourseStartTime>
            <CourseNumber>12345</CourseNumber>
          </CourseInfo>
          <CourseInfo>
            <CourseName>B</CourseName>
            <CourseWorkDay>Monday</CourseWorkDay>
            <CourseWorkDay>Tuesday</CourseWorkDay>
            <CourseStartTime>6:30am</CourseStartTime>
            <CourseNumber>98765</CourseNumber>
          </CourseInfo>
        </CourseData>
      </x:XData>
    </XmlDataProvider>
    <HierarchicalDataTemplate DataType="CourseInfo" ItemsSource ="{Binding XPath=CourseWorkDay}">
      <TextBlock Text="{Binding XPath=CourseName}" />
    </HierarchicalDataTemplate>
  </FrameworkElement.Resources>
  <StackPanel>
    <TreeView ItemsSource="{Binding Source={StaticResource myCourseData}, XPath=CourseInfo}" 
        Name="myTreeView" SelectedValuePath="CourseNumber"/>

    <TextBlock Margin="10">SelectedValuePath: </TextBlock>
    <TextBlock Margin="10" Text="{Binding ElementName=myTreeView, Path=SelectedValuePath}"/>
    <TextBlock Margin="10">SelectedValue: </TextBlock>
    <TextBlock Margin="10" Text="{Binding ElementName=myTreeView, Path=SelectedValue}"/>

  </StackPanel>     

</Page>