C# 5.0 Programmer's Reference

376 ❘ CHAPTER 16 Printing
This code sets PagesPrinted to 0 because no pages have been printed yet during this round of printing.
It then copies the ParagraphInfo structures from the AllParagraphs list (which holds all the
data) into the ParagraphsToPrint list (which holds those paragraphs that have not yet been printed).
Before it prints each page, the PrintDocument object raises its QueryPageSettings event. The
program uses the following code to catch this event and prepare the next page for printing.
// Set the margins for the next page.
private void bookletPrintDocument_QueryPageSettings(object sender,
QueryPageSettingsEventArgs e)
{
// Use a 1 inch gutter. (Printer units are 1/100th inch).
const int gutter = 100;
}
// See if the next page will be the first, odd, or even.
if (PagesPrinted == 0)
{
// The first page. Increase the left margin.
e.PageSettings.Margins.Left += gutter;
}
else if ((PagesPrinted % 2) == 0)
{
// It's an odd page. Shift the margins right.
e.PageSettings.Margins.Left += gutter;
e.PageSettings.Margins.Right -= gutter;
}
else
{
// It's an even page. Shift the margins left.
e.PageSettings.Margins.Left -= gutter;
e.PageSettings.Margins.Right += gutter;
}
This code positions the new page’s gutter. If this is the first page, then the page’s margins have their
default values and do not include a gutter. In that case, the code increases the left margin to add a
1-inch gutter.
If this isn’t the first page, the code determines whether it is an odd or even page. If this is an even page,
then the previous page was odd, so the gutter is currently on the left. To move the gutter to the right
side of the page, the code adds 1 inch to the left margin and subtracts 1 inch from the right margin.
Similarly, if this is an even page, the code subtracts 1 inch from the left margin and adds 1 inch to
the right margin.
After the QueryPageSettings event finishes, the PrintDocument object raises its PrintPage event
to generate the next printed page. The program’s PrintPage event handler is fairly long, so the following
paragraphs describe it in pieces. (Download the example to see it all in one chunk.)
The following code shows how the event handler starts.
private void bookletPrintDocument_PrintPage(object sender, PrintPageEventArgs e)
{
// Increment the page number.
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