Point Hit Test with VisualTreeHelper.HitTest : UI Element « Windows Presentation Foundation « VB.Net Tutorial

1. VB.Net Tutorial
2. Windows Presentation Foundation
3. UI Element

<StackPanel xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  xmlns:d="http://schemas.microsoft.com/expression/interactivedesigner/2006"
  mc:Ignorable="d"
  x:Class="InputExamples.PointHitTest" 
  Width="640" Height="480">

  <StackPanel.Resources>
    <Storyboard x:Key="OnLoaded"/>
  </StackPanel.Resources>
  <StackPanel.Triggers>
    <EventTrigger RoutedEvent="FrameworkElement.Loaded">
      <BeginStoryboard x:Name="OnLoaded_BeginStoryboard" Storyboard="{DynamicResource OnLoaded}"/>
    </EventTrigger>
  </StackPanel.Triggers>
  <Rectangle Fill="Red" Margin="20" Width="200" Height="200" x:Name="RectangleArea"/>
</StackPanel>
//File:Window.xaml.vb

Imports System
Imports System.IO
Imports System.Net
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Data
Imports System.Windows.Input
Imports System.Windows.Media
Imports System.Windows.Media.Animation
Imports System.Windows.Navigation

Namespace InputExamples
  Public Partial Class PointHitTest
    Public Sub New()
      Me.InitializeComponent()
    End Sub

    Protected Overrides Sub OnInitialized(e As EventArgs)
      MyBase.OnInitialized(e)
      AddHandler CompositionTarget.Rendering, AddressOf Me.CompositionTarget_Rendering
    End Sub

    Private Sub CompositionTarget_Rendering(sender As Object, e As EventArgs)
      Dim position As Point = Mouse.GetPosition(RectangleArea)
      VisualTreeHelper.HitTest(RectangleArea, Nothing, New HitTestResultCallback(AddressOf HitTestResultHandler), New PointHitTestParameters(position))
    End Sub

    Public Function HitTestResultHandler(result As HitTestResult) As HitTestResultBehavior
      Dim hitResult As PointHitTestResult = DirectCast(result, PointHitTestResult)
      Console.WriteLine(DirectCast(hitResult.VisualHit, FrameworkElement).Name)
      Console.WriteLine(hitResult.PointHit.ToString())
      Return HitTestResultBehavior.[Continue]
    End Function
  End Class
End Namespace

16.50.UI Element
	16.50.1.	Find enclosure component
	16.50.2.	Clear locally set values and restore the default values of dependency properties
	16.50.3.	PresentationTraceSources.SetTraceLevel(binding,PresentationTraceLevel.High);
	16.50.4.	UI Element Mouse Clicked Events
	16.50.5.	Programmatically Extract an Element's Style with DefaultStyleKeyProperty
	16.50.6.	Print Logical Tree
	16.50.7.	Print Visual Tree
	16.50.8.	About Dialog with Tree Walking
	16.50.9.	Changing graphical elements
	16.50.10.	UIElement Count
	16.50.11.	Use Linq to get control from a container
	16.50.12.	Find inner visual element
	16.50.13.	Logical Visual Tree Sample
	16.50.14.	Point Hit Test with VisualTreeHelper.HitTest
	16.50.15.	Change the Visibility property of a UIElement.
	16.50.16.	Mixing graphics with Control Elements