How to manipulate tcp sent packets and received packets in a certain application

Question

I would like to know what should I learn /what should I do because I want to do make a c# application to achieve the followings:

• How to intercept tcp packets sent by a certain application and how to view information from packets.
  • packets received ( the same thing)

Answer 1

You can use the same library as Wireshark uses: Pcap.

Here's a tutorial : http://pcapdotnet.codeplex.com/wikipage?title=Pcap.Net%20Tutorial