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.NET Forum / Languages / C# / November 2006File i/o question
Is there a simple way to find out (1.) when a file is in use, (2.) and when any file in a directory is in use, so file access by another user can be blocked? I am asking this because I have to change a single user app into a multi-user app, while using FileShare parameters isn't possible due to the way the app was written. Adrian. Try and open it exclusively if it fails it is in use. try { using (FileStream i = File.Open(filename, FileMode.Open, FileAccess.Read, FileShare.None)) { return true; } } catch (IOException) { return false; } > Adrian < wrote: > Is there a simple way to find out [quoted text clipped - 8 lines] > > Adrian. > Try and open it exclusively if it fails it is in use. > [quoted text clipped - 23 lines] > > > > Adrian. The problem is that in one directory there are data files and files that contain all sorts of parameters, that are used by all sorts of shared methods. So just using a FileShare parameter of the data files per se won't do. The only thing I can think of conceptually, is ascertaining whether the directory is in use or not, and blocking use of the data files of it is. However, I am unable to conceive a method for doing that. Adrian. > Is there a simple way to find out > (1.) when a file is in use, Just try to open for writing and check if exception was thrown > (2.) and when any file in a directory is in use, > so file access by another user can be blocked? Exception will be arised  SignatureWBR, Michael Nemtsev :: blog: http://spaces.live.com/laflour "At times one remains faithful to a cause only because its opponents do not cease to be insipid." (c) Friedrich Nietzsche > > Is there a simple way to find out > > (1.) when a file is in use, [quoted text clipped - 5 lines] > > Exception will be arised The problem is that in one directory there are data files and files that contain all sorts of parameters, that are used by all sorts of shared methods. So just using a FileShare parameter of the data files per se won't do. The only thing I can think of conceptually, is ascertaining whether the directory is in use or not, and blocking use of the data files of it is. However, I am unable to conceive a method for doing that. Adrian. | > > Is there a simple way to find out | > > (1.) when a file is in use, [quoted text clipped - 15 lines] | whether the directory is in use or not, and blocking use of the data | files of it is. However, I am unable to conceive a method for doing that. There is no such thing like "Directory in use". If you want shared access to files in an application, you have to open the files for shared read or read/write access. For files shared for read-only access, there is nothing special to be done, for files opened in R/W access mode you need to coordinate the write accesses across the process boundaries, one way to do this is by using a global mutex. If you wan't finer grained write access control, you will have to lock file regions using FileStream.Lock/Unlock. Willy. > | > > Is there a simple way to find out > | > > (1.) when a file is in use, [quoted text clipped - 25 lines] > > Willy. *********************** Thank you, Adrian. Can't I simply put After a filestream fs has been opened for read: while(!fs.CanRead){} After a filestream fs has been opened for write: while(!fs.CanWrite){} Adrian Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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