WPF C#

    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.cs
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Input;
namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }
        void HandleButtonDown(object sender, MouseButtonEventArgs e)
        {
            StackPanel sourceStackPanel = e.Source as StackPanel;
            if (e.ButtonState == MouseButtonState.Pressed)
            {
                sourceStackPanel.Width = 200;
                sourceStackPanel.Height = 200;
            }else if (e.ButtonState == MouseButtonState.Released)
            {
                sourceStackPanel.Width = 100;
                sourceStackPanel.Height = 100;
            }
        }
    }
}