Take the 2-minute tour ×  I have a TextBlock that I need to
autosize to the width of a TreeView. The TreeView and the
TextBlock are both contained in a StackPanel. The StackPanel is
inside an Expander. The width of the TreeView should drive the
width of the other objects and I need the height of the
TextBlock to change to display the full text. All my efforts
have resulted in the TextBlock driving the width. Thanks!
<Expander IsEnabled="True" HorizontalAlignment="Right"
Margin="0,8,8,53" x:Name="ExpanderBookMarks" Width="Auto"
Foreground="#FF625B5B" ExpandDirection="Down" IsExpanded="True"
Header="Bookmarks" Visibility="Hidden">          <StackPanel
Name ="StackPanelBookmark" Orientation="Vertical"
Width="{wpf:Binding Path=Width, ElementName=trvBookmarks,
Mode=Default}">              <TreeView x:Name="trvBookmarks"
ItemsSource="{Binding}"
ItemTemplateSelector="{StaticResource BookmarkTemplateSelector}"
TreeViewItem.Selected="HandleTreeViewItemClick"
AllowDrop="True"/>