计算打印页数的有效方法？

Question

TLDR How can one efficiently determine the amount of pages that have to be printed?

** Just a note: I marked klugerama's answer as the answer to my question. I'm still open for other suggestions though!

Currently, I have an application in production which prints invoices. The printing itself isn't a problem: customer information, invoice details etc are printed as they should be. However, users are complaining about the time it takes my software to send the print job to the printer.

At the moment, I have implemented a rather inefficient way to print. In order to know how many pages I have to print, I do a 'dry run' of the print job and cancel it before it gets sent to the printer. Then I count the number of pages the print job contains and add that information to the print job that actually does get sent to the printer. To do this, I 'abuse' the PrintDocument.PrintPage method. After doing so, I can print "Page 1/2 - Page 2/2" etc.

I'm currently thinking about handling this in a different way. I know which margins I have in a page, like the header and the footer. Ergo, the space between header and footer is the available space to print article information (name, price etc). If I calculate the height of the string (using Graphics.MeasureString ), I can tell when the articles take up more space on a page that's available for printing.

Previously, printing could take up to a minute before actually getting sent to the printer (taken into account the clients which run the software aren't the fastest around). I have implemented this method, and printing now takes about 5-10 seconds. However, I'm wondering if this is the way to go. I can't imagine I'm the only one dealing with this issue; how do you deal with this?

I'm also open to completely different approaches.

Answer 1

What you are doing sounds like the way to go. But...

You could instead output to XML and use XSLT to style the output, which would handle pagination for you. Note that this would likely require a pretty substantial refactoring effort, so depending on your situation it's likely not feasible, but it's an option.

It would also provide some potential flexibility down the road, as it provides a more modular approach. This would allow you to more easily provide other output options, like HTML & PDF. It may also make "print preview" easier.