VB.net won't run on the X8.
If you're wanting to have a VB.net app contact the X8 for information that is possible. You would need to setup a python application that would run on the X8. It would listen for TCP or UDP traffic. Upon getting that traffic the python app on the X8 would open a zigbee socket and communicate with your controller. It would get the data back from it and then forward it back to your VB.net app, via TCP or UDP.