WPF/Silverlight: Printing of Visuals - Drawbacks - wpf

Question

I read once or twice that printing visuals from WPF/Silverlight has some drawbacks so people usually tend to use FlowDocument or FixedDocument for printing.
I want to print some graphically intense dashboards and printing the visual directly seems to be the easiest way to go. I don't have to care about pagination since every dashboard I want to print is supposed to fit on one page.
Are there still drawbacks I must consider before choosing this way of printing?

Answer 1

You can print Visual objects by hosting them in a FrameworkElement and then adding the FrameworkElement to a FixedDocument as content of a FixedPage. The Visual host looks like this:
/// <summary>
/// Implements a FrameworkElement host for a Visual
/// </summary>
public class VisualHost : FrameworkElement
{
Visual _visual;
/// <summary>
/// Gets the number of visual children (always 1)
/// </summary>
protected override int VisualChildrenCount
{
get { return 1; }
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="visual">The visual to host</param>
public VisualHost(Visual visual)
{
_visual = visual;
AddVisualChild(_visual);
AddLogicalChild(_visual);
}
/// <summary>
/// Get the specified visual child (always
/// </summary>
/// <param name="index">Index of visual (should always be 0)</param>
/// <returns>The visual</returns>
protected override Visual GetVisualChild(int index)
{
if (index != 0)
throw new ArgumentOutOfRangeException("index out of range");
return _visual;
}
}
Then you can add them and print them like this:
// Start the fixed document
FixedDocument fixedDoc = new FixedDocument();
Point margin = new Point(96/2, 96/2); // Half inch margins
// Add the visuals
foreach (Visual nextVisual in visualCollection)
{
// Host the visual
VisualHost host = new VisualHost(nextVisual);
Canvas canvas = new Canvas();
Canvas.SetLeft(host, margin.X);
Canvas.SetTop(host, margin.Y);
canvas.Children.Add(host);
// Make a FixedPage out of the canvas and add it to the document
PageContent pageContent = new PageContent();
FixedPage fixedPage = new FixedPage();
fixedPage.Children.Add(canvas);
((System.Windows.Markup.IAddChild)pageContent).AddChild(fixedPage);
fixedDoc.Pages.Add(pageContent);
}
// Write the finished FixedDocument to the print queue
XpsDocumentWriter xpsDocumentWriter = PrintQueue.CreateXpsDocumentWriter(queue);
xpsDocumentWriter.Write(fixedDoc);