.NET SerialPort DataReceived event not firing

Question

I have a WPF test app for evaluating event-based serial port communication (vs. polling the serial port). The problem is that the DataReceived event doesn\'t seem to be fir

Answer 1

I ran into a similarly odd problem recently, but only on some machines. As Dave Swersky noted, this may have been a threading issue, especially if you were running under .NET 4.0 or later.

In .NET 4.0 the event handler is triggered on a ThreadPool thread, and under certain circumstances there may be a substantial delay before that occurs. (In my code, which had been working perfectly under .NET 2.0, problems were observed as soon as we upgraded to .NET 4.5. The event handler would often be triggered much later than would be expected, and sometimes it would not get triggered at all!)

Calling ThreadPool.SetMinThreads(...) with a bigger value for the completion threads made the issue disappear as quickly as it had arrived. In the context of our application ThreadPool.SetMinThreads(2, 4) was sufficient. On the machines where the problem was observed, the default values (as obtained by calling ThreadPool.SetMinThreads) were both 2.