WPF Generic eventhandler for various event

public MainWindow()
{
    InitializeComponent();
    this.AddHandler(ListBox.SelectionChangedEvent,
        new SelectionChangedEventHandler(GenericHandler));

    this.AddHandler(Button.ClickEvent, 
        new RoutedEventHandler(GenericHandler));
}        

void GenericHandler(object sender, RoutedEventArgs e)
{
    if(e.RoutedEvent==Button.ClickEvent)
    {
        MessageBox.Show("You just clicked " + e.Source);
    }
    else if(e.RoutedEvent==ListBox.SelectionChangedEvent)
    {
        SelectionChangedEventArgs sce=e as SelectionChangedEventArgs;
        if(sce.AddedItems.Count>0)
        {
            MessageBox.Show("You just selected "+sce.AddedItems[0]);
        }
    }
}

 

<Window x:Class="WpfApp343.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp343"        
        SizeToContent="WidthAndHeight"
        Background="OrangeRed"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <StackPanel>
        <Label FontWeight="Bold" FontSize="20" Foreground="White">
            WPF 4 Unleashed
        </Label>
        <Label>@ 2010 SMAS Publishing</Label>
        <Label>Installed Chapters:</Label>
        <ListBox>
            <ListBoxItem>Chapter 1</ListBoxItem>
            <ListBoxItem>Chapter 2</ListBoxItem>
        </ListBox>
        <StackPanel Orientation="Horizontal"
                    HorizontalAlignment="Center">
            <Button MinWidth="75" Margin="10">Help</Button>
            <Button MinWidth="75" Margin="10">OK</Button>
        </StackPanel>
        <StatusBar>You have successfully registered this product.</StatusBar>
    </StackPanel>
</Window>