PDFsharp is a .NET library for creating and modifying Adobe PDF documents programmatically from any .NET language like C# or VB.NET. PDFsharp defines classes for the objects found in PDF files, so you never have to deal with IDs or references directly.
The downloads include MigraDoc Foundation, a .NET library for creating documents on the fly (supports PDF and RTF).

PDFsharp is the .NET library that easily creates and processes PDF documents on the fly from any .NET language. The same drawing routines can be used to create PDF documents, draw on the screen, or send output to any printer.

MigraDoc Foundation is the .NET library that easily creates documents based on an object model with paragraphs, tables, styles, etc. and renders them into PDF, XPS, or RTF.

Use PDFsharp or MigraDoc?
* Use PDFsharp to create PDF files only, but be able to control every pixel and every line that is drawn.
* Use MigraDoc to create PDF and RTF files and to enjoy the comfort of a word processor.