DotNet program update date from Navision

Hello,
I have a Dotnet (C # Winforms) program which communicates with Navision via webservice.
In this case, it displays a list of the production orders for a particular Work Center.
Now the list should update, if in Navision a new FA is created or an existing FA is changed.

Of course I could make a timer in the C # program.
But it would rather be updated only if Navision has new data (Publish Function).
How could I create a communication here or trigger an event in the C # program.

Thanks,
stony