The process cannot access the file 'C:\inetpub\wwwroot\MyApp\5-23-2011.log' because it is being used by another process

问题

I have a singleton logger which is used inside an ASP.NET application. Sometimes I get The process cannot access the file error on this line:

StreamWriter sw = new StreamWriter("Path to log file", true);

I checked file handle by Process Explorer and w3wp.exe owns the handle so it seems different threads from the same process caused the problem.

I have used a lock around the above code, but still I get the error. How can I make sure all threads can use the same stream safely?

回答1:

Don't open the log file more than once; just open it when the application starts, close it at exit (and flush it often.) Opening and closing more than once is just inefficient.

来源：https://stackoverflow.com/questions/6092421/the-process-cannot-access-the-file-c-inetpub-wwwroot-myapp-5-23-2011-log-beca