Hi have a VB6 Windows application (old.exe) and a separate C# Winforms application (new.exe). They both run on the same Windows machine.
I have access to both the VB6 and the C# source code, but the apps need to remain separate.
If both are running and have knowledge of each other (process Id), what’s the best way to send a message from one window to the other?
Update:
In this case, I’m only talking about very infrequent and small messages – e.g. change the tab you’re looking at using a small message like, “Invoice 67”
Bi-directional messaging would be great, but VB6 to .Net is the most important.
Neither of the two prior answers consider the fact that this may be a multi-tentant environment or even span you domain. As you move into distributed systems you shold consider messaging as opposed to inter-process communication, which over time will limit scalability.
For on-premise solutions consider MSMQ, there is a multitude of documentation out there, demonstrating the simplicity of this messaging infrastructure.
for broader scenarios, you should consider Windows Azure Storage Queues, you get an almost identical usability, but with a broader accessibility and improved management tools.
MSMQ is domain-specific, by Azure spans the globe.