Customize PrintDialog Window in WPF
It's actually possible to extend common dialogs with .NET. I found this article on MSDN. However, I'm not sure whether this also applies to the print dialog or whether it can still be done, but I suggest you read that first.
"C# provides a standard PrintDialog which has all the basic print dialog functionality. Since it is declared as a sealed class, there is no way to extend it through C# native syntax."
Please see the following link:http://www.codeproject.com/Articles/16797/Extending-C-PrintDialog-Part-I
You can always create your own "Printing dialog screen" from scratch , then you can add your drop down with the ammount of lines to print(dropdown) witch you then get from the listbox(concatenating or build string) and send to a specified printer.