Control.FontStyle, propriété

<Button Name="btn4" FontStyle="Normal" 
        Click="ChangeFontStyle">
  FontStyle
</Button>

Private Sub ChangeFontStyle(ByVal Sender As Object, ByVal e As RoutedEventArgs)

    If (btn4.FontStyle = FontStyles.Italic) Then

        btn4.FontStyle = FontStyles.Normal
        btn4.Content = "FontStyle"

    Else

        btn4.FontStyle = FontStyles.Italic
        btn4.Content = "Control font style changes from Normal to Italic."
    End If
End Sub

void ChangeFontStyle(object sender, RoutedEventArgs e)
{
    if (btn4.FontStyle == FontStyles.Italic)
    {
        btn4.FontStyle = FontStyles.Normal;
        btn4.Content = "FontStyle";
    }
    else
    {
        btn4.FontStyle = FontStyles.Italic;
        btn4.Content = "Control font style changes from Normal to Italic.";
    }
}