how to convert pdf file to doc/txt file

i want to convert a pdf file to text file and then updates that file..after updating i want to convert that file again in pdf format.

I need to find a given string/text in PDF file. I am not supposed to use any third party library so are there any classes in .net framework base library which can help me do the same ?

I am not sure but if you are using Acrobat Professional or Reader 8.0 then you can use the libraries provided by them.

Well I told you I am not too sure about the usage of the library......But you can check the Acrobat libraries in the COM Components tab when you choose "Add Reference".

Second if you choose to use the acrobat viewer control then it's easy, as it will provide you the full interface as the same as you have in the Acrobat Reader with all the functionalitites. I recommend try using the user control. I hope this shoul help.

There are no classes to manipulate PDF files in the Base Class Library of the .NET Framework, so I am afraid you have to resort to 3rd party libraries. Searching for it on the internet seems to be a good idea. Here is one I just come across for your reference