Our software is written in C# and needs to connect to SAP. As some of our customers use older versions of SAP, and others don't have SAP PI, we can't connect through webservices.
I tried to connect to SAP through the SAP NetWeaver Remote Function Call Library (sapnwrfc.dll) as follows:
Running this code gives a DllNotFoundException:
Unable to load DLL 'sapnwrfc.dll': This application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem. (Exception from HRESULT: 0x800736B1)
Running the standard connect-to-C++-from-C# example
[DllImport("user32.dll", CharSet = CharSet.Unicode)]
public static extern int MessageBox(IntPtr hWnd, String text, String caption, uint type);
MessageBox(new IntPtr(0), "Hello World!", "Hello Dialog", 0);
works fine.
Any suggestions how to make this work fine (so that we don't need to workaround this problem by writing a Java proxy using JCo)?
Did you check with the Dependency Viewer if you are missing some DLL? I did once write a managed wrapper for the rfc library (at least part of it) and I remember having a problem with some of the rfc libraries I downloaded. One version simply did not work and I did not figure out what was wrong. Another version (older) worked just fine.
I did however have problems with the unicode library (some memory access problem that appeared randomly) so I had to switch to the non-unicode version...
If I had to do something like this again, I would very seriously consider to buy a connector: http://www.theobald-software.com/en/products/erpconnect.htm
I cannot say if it is any good, but they seem to be around for a while now.