Pump Messages During Long Operations

[Mark Ingram]

"The CLR has been unable to transition from COM context 0x1b0f58 to COM
context 0x1b10c8 for 60 seconds. The thread that owns the destination
context/apartment is most likely either doing a non pumping wait or
processing a very long running operation without pumping Windows
messages. This situation generally has a negative performance impact and
may even lead to the application becoming non responsive or memory usage
accumulating continually over time. To avoid this problem, all single
threaded apartment (STA) threads should use pumping wait primitives
(such as CoWaitForMultipleHandles) and routinely pump messages during
long running operations."

So, in my C# loop (reading in a bunch of images) - how do I pump windows
messages so that my application responds?

 

[David Browne]

"The CLR has been unable to transition from COM context 0x1b0f58 to COM
context 0x1b10c8 for 60 seconds. The thread that owns the destination
context/apartment is most likely either doing a non pumping wait or
processing a very long running operation without pumping Windows messages.
This situation generally has a negative performance impact and may even
lead to the application becoming non responsive or memory usage
accumulating continually over time. To avoid this problem, all single
threaded apartment (STA) threads should use pumping wait primitives (such
as CoWaitForMultipleHandles) and routinely pump messages during long
running operations."

So, in my C# loop (reading in a bunch of images) - how do I pump windows
messages so that my application responds?

You don't. Instead, avoid calling STA COM components from non-STA threads.

David

 

[Carl Daniel [VC++ MVP]]

"The CLR has been unable to transition from COM context 0x1b0f58 to
COM context 0x1b10c8 for 60 seconds. The thread that owns the
destination context/apartment is most likely either doing a non
pumping wait or processing a very long running operation without
pumping Windows messages. This situation generally has a negative
performance impact and may even lead to the application becoming non
responsive or memory usage accumulating continually over time. To
avoid this problem, all single threaded apartment (STA) threads
should use pumping wait primitives (such as CoWaitForMultipleHandles)
and routinely pump messages during long running operations."

So, in my C# loop (reading in a bunch of images) - how do I pump
windows messages so that my application responds?

The crude way (that lots of people will probably jump on and say "don't do
that") is to call Application.DoEvents every now and then while you're
reading files (e.g. once per file).

The right way is to move your lengthy processing to a worker thread. Use
async delegates, the thread pool, the new BackgroundWorker (2.0) class, or
the System.Threading API directly. Be aware that once you move processing
to a worker thread, you need to marshall all UI access into the correct
thread using Control.{Begin}Invoke. It's not allowed under Winforms 2.0 for
a thread other than the owning thread to touch any GUI compoent. (It was
allowed in 1.1 and before, but there was no guarantee that it would work,
and it's prone to deadlocks. This is a core Windows limitation, not
anything specific to Winforms).

-cd

 

[Mark Ingram]

The crude way (that lots of people will probably jump on and say "don't do
that") is to call Application.DoEvents every now and then while you're
reading files (e.g. once per file).

The right way is to move your lengthy processing to a worker thread. Use
async delegates, the thread pool, the new BackgroundWorker (2.0) class, or
the System.Threading API directly. Be aware that once you move processing
to a worker thread, you need to marshall all UI access into the correct
thread using Control.{Begin}Invoke. It's not allowed under Winforms 2.0 for
a thread other than the owning thread to touch any GUI compoent. (It was
allowed in 1.1 and before, but there was no guarantee that it would work,
and it's prone to deadlocks. This is a core Windows limitation, not
anything specific to Winforms).

-cd

Ahh, DoEvents, that was the hack I was looking for. A thread is
preferable long term, but for now I just want to get rid of the error

Thanks,