In previous tip, Abhishek discussed about basic of Logical and Visual Tree in WPF. In this tip I am going to explain how you can retrieve and examine the Visual Tree programmatically in WPF. The VisualTreeHelper provides few API Methods GetChildrenCount(), GetChild() and GetParent() using which you can get details of the Visual Tree structure.
VisualTreeHelper.GetChildrenCount() method returns the number of child visuals, that the parent visual contains and VisualTreeHelper.GetChild() method helps to get the index value of the child visual object. Using the VisualTreeHelper.GetChild() you can traverse through the visual tree of any window or child control.
To implement the same, below is the snippet for XAML where I have one Button and TreeView inside a Stack Panel and Grid is to top parent container.
On the Click of the Button we will be generating the Visual Tree. 
You must have noticed I have provided “this” as argument to the method, which means, I want to generate the Visual Tree by considering “Main Window” as parent.
Below is the implementation for the ShowWPFVisualTree() and AddElementsAtVisualTree() method.
You are done, Click on “Show Visual Tree” button and you will get the complement visual Tree as show in below image.
If you want to make this bit simple, while calling ShowWPFVisualTree(), instead of passing “this” as argument, pass “grid1” as argument and run the application. You will find tree is starting from a Grid Control which contains a “Stack Panel” and Button and TreeView are the child controls.
You can Expand Button and TreeView ( Collapsed in the above image ) to get the inner tree structure.
Below is the complete Code Snippet
XAML :
<Window x:Class="WPFVisualTree.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Show Visual Tree" Height="450" Width="536">
<Grid x:Name="grid1">
<StackPanel>
<Button Content="Show Visual Tree"
Name="btnShowVisualTree"
Margin="40,10,0,0"
Click="btnShowVisualTree_Click"
Width="150"/>
<TreeView Margin="0,10,0,0"
Name="treeVisual" />
</StackPanel>
</Grid>
</Window>
Class :
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
///
///
/// The source of the event.
/// The
{
this.ShowWPFVisualTree(this.grid1);
}
///
///
/// The element.
public void ShowWPFVisualTree(DependencyObject element)
{
treeVisual.Items.Clear();
AddElementsAtVisualTree(element, null);
}
///
///
/// The element.
/// The previtem.
private void AddElementsAtVisualTree(DependencyObject element, TreeViewItem previtem)
{
TreeViewItem item = new TreeViewItem();
item.Header = element.GetType().Name;
item.IsExpanded = true;
if (previtem == null)
{
treeVisual.Items.Add(item);
}
else
{
previtem.Items.Add(item);
}
int totalElementcount = VisualTreeHelper.GetChildrenCount(element);
for (int counter = 0; counter < totalElementcount; counter++) { AddElementsAtVisualTree(VisualTreeHelper.GetChild(element, counter), item); } } } [/code] Hope this will helps ! Cheers ! Aj
