C# Problem with opened files

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Is there a way to check if a file is in use?

Is there a way to close a file in C#?

if(File.Exists(TEMP_FILENAME))
            File.Delete(TEMP_FILENAME);

The above code complains that file is already used by another process.

Is there a way to check the open file handles in VS 2008?

could you post the code that brings you here, there may be clues to a bigger problem. — gingerbreadboy, Jan 20 '10 at 19:21

score 2 · Accepted Answer · answered Jan 20 '10 at 19:19

2

Close any streams using the file in your application.

If the error is due to another running applicaton, it's best to just try the operation, and deal with the failure. If you check, then try to perform the operation, you create a race condition. If the delete fails (whether due to file in use or permissions), just deal with the problem then.

answered Jan 20 '10 at 19:19

Yuliy

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Actually the file is an image file but I didn't call dispose method on it. I fixed it and it started working. Thank you Yuliy – Boolean Jan 20 '10 at 20:17
you probably still want to do the checking for usage - it's better to put the check in now than have a weird bug popup later. – aronchick Jan 20 '10 at 20:27
aronchick: it's better to wrap the delete in a try-catch, than do if(can delete) File.Delete. This is so you can avoid a TOCTTOU (Time of Check to Time of Use) bug. – Yuliy Jan 20 '10 at 21:05

score 1 · Answer 2 · edited May 23 '17 at 11:59

1

I HAVE had this happen in VS2008 when running a program, stopping the execution once I've opened a file, and then running again and trying to do anything with the file. When that happens, the only way I've found to fix it is to close VS and re-open it, or kill the *.vshost.exe process, in order to release the file. I've never really looked into why it happens, but I assume it's because the actual process that runs as your app from VS is the *.vshost.exe file, which doesn't close when you end the execution of your program.

Also, to prevent this from happening, always either be sure to properly close your filestreams, or utilize a using block. Make sure that this part of your code executes before ending execution via VS.

If this ISN'T what's happening, check the answer provided by mkus for how to see if another application has your file locked.

edited May 23 '17 at 11:59

Community

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answered Jan 20 '10 at 19:32

Nathan Wheeler

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Yep, this has happened to me too... normally I just restart VS. Thanks for the tip with stopping the vshost.exe process, I'll try that next time it happens. – Charlie Salts Jan 20 '10 at 19:49
I usually restart VS at that point, and often my computer as well, since I normally only restart once a week, it's an opportune time to restart and grab some fresh coffee... If I'm right in the middle of my train of thought when it happens though, it's a lot faster just to kill the vshost process and continue what I was doing rather than be derailed by the five minute wait for all of my stuff to come back up. – Nathan Wheeler Jan 20 '10 at 20:02

score 0 · Answer 3 · edited Nov 28 '16 at 13:32

0

See if you can acquire a safehandle. This is something again unmanaged stuff. If you can acquire a safehandle it probably means the file is free for use.

Refer this link

edited Nov 28 '16 at 13:32

Mong Zhu

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answered Jan 20 '10 at 19:35

deostroll

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C# Problem with opened files

3 Answers3