I would need to edit a pdf at runtime in C#.NET. Is this possible? Like copying things in the pdf, editing textfields, ...?
iText# (iTextSharp) is a port of the iText open source java library for PDF generation written entirely in C# for the .NET platform.
It is definitely possible, but not with what is built-in to .NET (unless you are a PDF format guru and can roll your own). I've mostly used Aspose for manipulating PDFs, but there are a lot of toolkits out there. Personally, I think Aspose is a little rough around the edges but not moreso than other kits.
Well there's iTextSharp : http://sourceforge.net/projects/itextsharp/ with which you can write pdf files, but I don't think it has editing (reading pdf) capabilities, or they will be limited. I've never found a way to edit PDF's, unless you buy some third party tool ...
ITextSharp is good for adding things to a PDF.
These PDF components are also pretty good: www.tallcomponents.com