Control.Foreground, propriété

<Button Name="btn1" Foreground="Black" 
        Click="ChangeForeground">
  Foreground
</Button>

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

    If (Equals(btn1.Foreground, Brushes.Green)) Then

        btn1.Foreground = Brushes.Black
        btn1.Content = "Foreground"

    Else

        btn1.Foreground = Brushes.Green
        btn1.Content = "Control foreground(text) changes from black to green."
    End If
End Sub

void ChangeForeground(object sender, RoutedEventArgs e)
{
    if (btn1.Foreground == Brushes.Green)
    {
        btn1.Foreground = Brushes.Black;
        btn1.Content = "Foreground";
    }
    else
    {
        btn1.Foreground = Brushes.Green;
        btn1.Content = "Control foreground(text) changes from black to green.";
    }
}