InkCanvas inkCanvas1 = new InkCanvas();
DrawingAttributes inkDA;
DrawingAttributes highlighterDA;
bool useHighlighter = false;

// Add an InkCanvas to the window, and allow the user to 
// switch between using a green pen and a purple highlighter 
// on the InkCanvas.
private void WindowLoaded(object sender, EventArgs e)
{
    inkCanvas1.Background = Brushes.DarkSlateBlue;
    inkCanvas1.DefaultDrawingAttributes.Color = Colors.SpringGreen;

    root.Children.Add(inkCanvas1);

    // Set up the DrawingAttributes for the pen.
    inkDA = new DrawingAttributes();
    inkDA.Color = Colors.SpringGreen;
    inkDA.Height = 5;
    inkDA.Width = 5;
    inkDA.FitToCurve = false;

    // Set up the DrawingAttributes for the highlighter.
    highlighterDA = new DrawingAttributes();
    highlighterDA.Color = Colors.Orchid;
    highlighterDA.IsHighlighter = true;
    highlighterDA.IgnorePressure = true;
    highlighterDA.StylusTip = StylusTip.Rectangle;
    highlighterDA.Height = 30;
    highlighterDA.Width = 10;

    inkCanvas1.DefaultDrawingAttributes = inkDA;
}

// Create a button called switchHighlighter and use 
// SwitchHighlighter_Click to handle the Click event.  
// The useHighlighter variable is a boolean that indicates
// whether the InkCanvas renders ink as a highlighter.

// Switch between using the 'pen' DrawingAttributes and the 
// 'highlighter' DrawingAttributes.
void SwitchHighlighter_Click(Object sender, RoutedEventArgs e)
{
    useHighlighter = !useHighlighter;
    
    if (useHighlighter)
    {
        switchHighlighter.Content = "Use Pen";
        inkCanvas1.DefaultDrawingAttributes = highlighterDA;
    }
    else
    {
        switchHighlighter.Content = "Use Highlighter";
        inkCanvas1.DefaultDrawingAttributes = inkDA;
    }
}