SAP's documentation suggests using a line similar to the following to create a connection to SAP:
RfcDestinationManager.RegisterDestinationConfiguration(new Config());
where Config() is a class that contains connection settings.
This works fine, except, you occasionally get the error, "Destination configuration already initialized", because the connection hasn't timed out. SAP's documentation that I've seen (the .chm help file and the "Overview" document) doesn't address this issue at all, and their sample code doesn't contain any examples of how to close a connection.
I've found that the following code works:
Config c = new Config();
RfcDestinationManager.RegisterDestinationConfiguration(c);
...
(processing code)
...
RfcDestinationManager.UnregisterDestinationConfiguration(c);
However, if you've just tried to connect without using "unregister", you'll have to wait until the old connection times out itself before trying the code above (the sample config code SAP provides keeps the connection open for 10 minutes).
Overall, I've found the new SAP Connector 3 to be a HUGE step up from v2, though it is quite a pain having to re-write all of my v2 applications. But I easily prefer a few months of re-writing over being tied to VS2003. Thanks, SAP, for updating this - I thought you had forgotten about us .NET developers.
