WPF

<Window x:Class="WpfApplication4.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Grid>
        <Button Name="btn1" Background="Pink"
        BorderBrush="Black" BorderThickness="1"
        Click="OnClick1" ClickMode="Hover">
  ClickMe1
</Button>

<Button Name="btn2" Background="LightBlue"
        BorderBrush="Black" BorderThickness="1"
        Click="OnClick2" ClickMode="Press">
  ClickMe2
</Button>

<Button Name="btn3"
        Click="OnClick3" ClickMode="Release">
  Reset
</Button>
    </Grid>
</Window>
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApplication4
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

            void OnClick1(object sender, RoutedEventArgs e)
        {
            btn1.Background = Brushes.LightBlue;
        }

        void OnClick2(object sender, RoutedEventArgs e)
        {
            btn2.Background = Brushes.Pink;
        }

        void OnClick3(object sender, RoutedEventArgs e)
        {
            btn1.Background = Brushes.Pink;
            btn2.Background = Brushes.LightBlue;
        }

    }
}