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Hello !
I have an application on vb.net 2017 , that reads from excel and save to database.
When I process large data from excel , at some point the application stop , and inside visual studio I get this error :
Managed Debugging Assistant 'ContextSwitchDeadlock' : 'The CLR has been unable to transition from COM context 0x1b387fb0 to COM context 0x1b387e88 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.'
If I press Continue inside visual studio , the program continue to execute and finish the job without error.
But every time I have repeated the proces i get that error .
What can I do ?
Thank you !
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desanti wrote: What can I do ?
Offer smaller files.
It's the same with any application in Windows; if it doesn't respond, it is assumed to be dead. If an application does so, Windows will offer to terminate the application.
Or disable the break in the IDE, saving you from having to press F5.
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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sorry , but my application does respond and it's not dead.
until the point that this error is displayed , all the data are saved on database .
1 second before this error is displayed , a record was saved on database.
But suddenly this error appear , and I have to press continue , and after the execution goes without problem until the end.
so , the application is alive , why windows consider it to be dead ?
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desanti wrote: sorry , but my application does respond and it's not dead.
until the point that this error is displayed , all the data are saved on database .
1 second before this error is displayed , a record was saved on database.
But suddenly this error appear , and I have to press continue , and after the execution goes without problem until the end.
so , the application is alive , why windows consider it to be dead ?
It says literally so in the error; "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."
If the app does not process messages, it is considered "not responding". Most apps that go into an uncontrolled loop do not respond to those messages, and it is a way of detecting if the app is still active. If it is doing a lot in one thread, then the thread won't be replying to messages.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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And what you propose as a solution , because I've read that I should use a background worker , but the problem is that I need to access the UI objects during the process and this is not possible on a background worker.
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Since you wont be changing the COM-control, You'd be either ignoring the message, or offering smaller files.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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I can't offer smaller files.
also I've read that I can do some configuration to ignore the message.
but the problem is , what about when I finish my program and install it to client pc ?
I've read also that I can use application.doevents.
But executing this on every step of the loop cause the program to slow down.
Is there way to call this only when necessary so windows can detect that my application is alive ?
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desanti wrote: also I've read that I can do some configuration to ignore the message.
but the problem is , what about when I finish my program and install it to client pc ?
You can; the IDE only breaks on exceptions that you want it to. What happens without the IDE can easily be tested by running your app outside of it. Then you'll know what happens on the client-PC.
desanti wrote: I've read also that I can use application.doevents.
No, you can't.
desanti wrote: But executing this on every step of the loop cause the program to slow down.
It is a loop inside a COM-component. Do you have the source to that control?
desanti wrote: Is there way to call this only when necessary so windows can detect that my application is alive ?
You application IS alive (and answering messages), but the COM-component that you're using is not. If you know WHY it is not answering messages, then it is not a problem. You simply wait for it to be done and hope it is not in an endless loop.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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If the loop is in your program, then it should be in a backgroundworker on its own thread. If the loop is inside the COM-component, you can't change much.
Application.DoEvents is a crutch for people doing too much on the UI-thread.
--edit
Go to the menu "Debug / Exceptions", find "Managed Debugging Assistants", uncheck ContextSwitchDeadlock.
And sometimes, the message is even bogus[^].
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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the loop is inside my program , but the problem is that inside the loop I use the values from some controls in my form ( there's a spreadsheet control that have all the data from excel file or directly written by user and some other textboxes that have all the data and parameters that I use on that loop). so I can't use a background worker because I've read that I can't use the UI controls inside it. Or I'm wrong !!!!!
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desanti wrote: so I can't use a background worker because I've read that I can't use the UI controls inside it. Or I'm wrong !!!!!
You can't access them directly, you'd have to do an invoke.
Is this actually occuring in the release-version?
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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Yes , I noticed at least 2-3 times in the release version.
I've tried with Application.doevents executed on every step of the loop , and no problems but the application slows down.
So i'm asking if there's a way to know the interval that windows check for application status , so i'm calling application.doevents not on every step of the loop but for example every x seconds ? Is this possible ?
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desanti wrote: So i'm asking if there's a way to know the interval that windows check for application status , so i'm calling application.doevents not on every step of the loop but for example every x seconds ? Is this possible ?
I never found any specification on how often Windows checks it, might even vary between versions. Instead of doing it every N seconds, you could do it after N items. Still, that metric may vary on another system.
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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But if you see my original error message , it says.... "60 seconds". Maybe this is the time or is another thing ?
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Yup, that's what it says, you're right. Get the current time before the loop.
Inside the loop, distract that value from the current time. If the difference is more than N seconds, call your doevents.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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a Timer object will be a help or no ?
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Which timer-object? There's multiple, and one of them relies on the application processing messages (ie, not being too busy).
It's easier to simply check inside the loop how much time has passed.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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The one from System.Windows.Forms says this in the docs;
Implements a timer that raises an event at user-defined intervals. This timer is optimized for use in Windows Forms applications and must be used in a window. Meaning it won't fire if it doesn't get to process the message.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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So , the only solution remain to manually calculate the time inside the loop.
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..which is not that hard; there's an example a few posts below.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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No, they haven't "solved" it. What they've done is gotten around the warning message without actually fixing the problem.
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If you think you have to use Application.DoEvents, this is a sign you're doing something very wrong.
modified 5-Dec-18 22:10pm.
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Solution? Ignore it. The message only shows up when debugging the app.
And you're wrong about the BackgroundWorker not having access to the controls. Technically, you don't have access to them, but you can get at the controls if you supply method to update the controls and Invoke calls to them. Using the BackgroundWorker, or some other threading/Task model, will free up the UI thread to pump messages. This will also make the warning message you're seeing disappear.
Also, if you're doing everything in this long-running operation on the UI (startup) thread, then your controls are not getting repainted anyway. If the UI thread is busy with your operation, it can't respond to all the WM_PAINT messages that are piling up in the message pump. So, during this operation, what could you possibly be updating in the controls since nobody can see those changes?
If you're going to do a long-running operation with control interactions, you have to do it correctly, otherwise you run into little issues like what you're seeing.
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