Document .Net is described as '«Document .Net» gives you API to do everything with a document in PDF, DOCX, DOC, RTF, HTML and Text formats'. There are five alternatives to Document.Net for Windows and Linux. The best alternative is iTextPDF, which is free. Other great apps like Document.Net are PDFSharp (Free, Open Source), PDF Clown (Free, Open Source), PDFjet (Freemium, Open Source) and ABCpdf .NET (Paid).
The leading Java and C# PDF Library SDK. A programmable Java and .NET PDF SDK library to create, manipulate and edit PDF documents. Convert Html files to pdf, Debug pdf files, extract data from PDF and more.
PDFsharp is the Open Source .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.