WPF VB.Net Tutorial

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="DetectMouseButtonState" Height="400" Width="400">
        MouseLeftButtonDown="HandleButtonDown" 
      MouseLeftButtonUp="HandleButtonDown" 
      Background="Red"
      DockPanel.Dock="Left">
    Click on Me
  

//File:Window.xaml.vb
Imports System
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media
Imports System.Windows.Input
Namespace WpfApplication1
  Public Partial Class Window1
    Inherits Window
    Public Sub New()
      InitializeComponent()
    End Sub
    Private Sub HandleButtonDown(sender As Object, e As MouseButtonEventArgs)
      Dim sourceStackPanel As StackPanel = TryCast(e.Source, StackPanel)
      If e.ButtonState = MouseButtonState.Pressed Then
        sourceStackPanel.Width = 200
        sourceStackPanel.Height = 200
      ElseIf e.ButtonState = MouseButtonState.Released Then
        sourceStackPanel.Width = 100
        sourceStackPanel.Height = 100
      End If
    End Sub
  End Class
End Namespace