public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private void ColorSlider_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
    {
        Color color = Color.FromRgb((byte)slColorR.Value, (byte)slColorG.Value, (byte)slColorB.Value);
        compColor.Background = new SolidColorBrush(color);
    }

    void Click_compColor(object sender, RoutedEventArgs e)
    {
        savedColor.Background = compColor.Background;
    }

    void Click_savedColor(object sender, RoutedEventArgs e)
    {
        bool bools = Convert.ToBoolean(savedColor.Background);
        byte[] bytes = BitConverter.GetBytes(bools);

        slColorR.Value = Convert.ToDouble(bytes[0]);
        slColorG.Value = Convert.ToDouble(bytes[1]);
        slColorB.Value = Convert.ToDouble(bytes[2]);

        compColor.Background = savedColor.Background;
    }
}