I collect some useful program here, hope it is useful for you.
- IKVM.NET version PDFBOX and the use case is on codeproject
- PDFtoText(pdf2text), it is one of XPDF program serials,btw, Xpdf is an open source viewer for Portable Document Format (PDF) files.
- iTextSharp, it can also do some easy job, have a look
PDFToText with ITextSharp–Extract text from PDF in C# (100% .NET)
- Adobe Acrobat (SDK), it is too expensive, and you have to know some C/C++ language.
only Acrobat is commercial, others are all open source.
if you know other program that can extract text from PDF under dotnet, please let me known, thanks in advance.