OPC with NI

Hello there

I'm new to OPC. I have 2 questions:

1. I would like my C# based application to have OPC client capabilities. I had integrated NationalInstruments.Net dll, and it worked. The thing is that the test was done with a dll I have taken from the trial version of Measurement Studio, and now it is expired. The question is, if I purchase a license for Measurement studio, would I will be able to add the dll to my systems, and it will work? Is there any limitation for this kind of usage?
2. For another application, I would like to integrate OPC server using. NationalInstruments.Net dl. Are there any code examples? I would like to get assistance