<UserControl x:Class="SilverlightTutorial.InspectorPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"><Canvas x:Name="LayoutRoot">
      <Grid Background="Cornsilk" Height="400" Width="600">
         <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
         </Grid.ColumnDefinitions>
         <StackPanel>
            <Button Content="Button" Height="23" Name="button1" Width="75" />
            <TextBlock Height="28" Name="label1" Width="120" Text="1234" />
            <ListBox Height="100" Name="listBox1" Width="120">
               <ListBoxItem>1</ListBoxItem>
               <ListBoxItem>2</ListBoxItem>
               <ListBoxItem>3</ListBoxItem>
               <ListBoxItem>
                  <Button Content="Button" Height="23" Name="button2" Width="75" />
               </ListBoxItem>
            </ListBox>
         </StackPanel>
         <Grid Grid.Column="1">
            <Grid.RowDefinitions>
               <RowDefinition Height="25" />
               <RowDefinition Height="*" />
            </Grid.RowDefinitions>
            <ToggleButton Content="Inspect" HorizontalAlignment="Center" Name="btnInspect" />
            <ScrollViewer VerticalScrollBarVisibility="Auto" Grid.Row="1">
               <TextBlock Name="textBlock1"  />
            </ScrollViewer>
         </Grid>
      </Grid>
      <Rectangle Name="rectHighlight" Stroke="Red" Width="100" Height="100" StrokeThickness="2" Visibility="Collapsed" />
   </Canvas>
</UserControl>

using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;namespace SilverlightTutorial
{
   public partial class InspectorPage : UserControl
   {
      public InspectorPage()
      {
         InitializeComponent();
         MouseMove += new MouseEventHandler(Page_MouseMove);
         MouseLeftButtonUp += (sender, args) =>
         {
            btnInspect.IsChecked = false;
            rectHighlight.Visibility = System.Windows.Visibility.Collapsed;
         };
      }void Page_MouseMove(object sender, MouseEventArgs e)
      {
         var dpObj = (e.OriginalSource as DependencyObject);
         if ((bool)btnInspect.IsChecked == false || dpObj == null || dpObj == rectHighlight)
            return;
                  Inspect(dpObj);
if (dpObj is UIElement)
         {
            var elm = (dpObj as UIElement);
            var generalTransform = elm.TransformToVisual(null);
            var point = generalTransform.Transform(new Point());
            SetHightlight(point, elm.RenderSize);
         }       
      }void SetHightlight(Point point, Size size)
      {
         rectHighlight.Visibility = System.Windows.Visibility.Visible;
         Canvas.SetLeft(rectHighlight, point.X);
         Canvas.SetTop(rectHighlight, point.Y);
         rectHighlight.Width = size.Width;
         rectHighlight.Height = size.Height;
      }void Inspect(DependencyObject dpObj)
      {
         var sbuf = new StringBuilder();
         Inspect(sbuf, 0, dpObj);
         textBlock1.Text = sbuf.ToString();
      }void Inspect(StringBuilder sbuf, int level, DependencyObject dpObj)
      {
         sbuf.AppendLine(new string(' ', 3 * level) + dpObj.GetType().Name);
         for (int i = 0; i < VisualTreeHelper.GetChildrenCount(dpObj); i++)
         {
            Inspect(sbuf, level + 1, VisualTreeHelper.GetChild(dpObj, i));
         }
      }
   }
}