C# connecting with InTouch.

Hi,
I'm was wondering, is there a possible way to connect programs written in C# or C++ to InTouch?

I know that there is a way to connect PLCSIM to InTouch by using nettoplcsim. Similarly, how do I connect program written in C# or C++ to InTouch? Do I have to write my own OPC server? If that is the only way then is there any free library that I can use?

Please advice..
Thanks.

I'm waiting for help in this regard..

For older InTouch versions I would have used DDE. But as far as I know, it's no longer supported with the actual Windows versions.

But you could use the official API:
http://www.codeproject.com/Articles/102533/Using-NET-with-Wonderware

or the Wonderware toolkit:
http://software.schneider-electric.com/products/wonderware/hmi-and-supervisory-control/toolkits/