How to connect to an SFTP server through .NET code

Is there any dll or code which i can use to connect to SFTP server and transfer the files to and from SFTP server through my VB or ASP .net Programs....if so pls help me out in.....

I do not know any :-(

take a look at these:

https://www.weonlydo.com/

https://www.nsoftware.com/

I was testing both some time ago. The nsoftware s/shell components comes with a sftp component, but it doen't work for VC++ (I reported that issue and they confirmed it)
I think that the wod components are better dessigned, but comes separately (sftp and ssh), so if you need ssh and sftp you have to buy both. I was testing sucessfully the wod components in vc++ and they worked fine, but I don't like that you have to install the .net framework in each machine you want to run your program. Also as thet are .net components, the overhead, amount of memory consumed and slow response times is a dissadvantage.