Search code examples
excelfilehelpers

"File already in use error" coming, but only when it is open in excel

I am using Filehelpers to read a log file. To be on safe side, I want to make sure that it does not throw "File Already in use" error. There might be a remote chance that the cleanup of the log writer might still be going on when the log parsing process launches.

I am using filehelpers "ReadFileAsDT" method and passing it the file name.

I went through the source code and found that it is opening the file in read only mode which is right.

var stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read, bufferSize, FileOptions.SequentialScan);
            this.Init(stream, encoding, detectEncodingFromByteOrderMarks, bufferSize);

But still, just to be sure I kept the log file open in the excel. And ran the log parser. And it gave the "File in use error".

If I keep the file open in Notepad, Wordpad or Notepad++, this error is not coming.

Is there anything special with the way the excel opens the files?

Solution

  • Excel maintains an active read/write lock on the file. This is true for ANY file that it opens and prevents other applications from reading/writing them half the time.

    Personally, if you want to have the log file open at the same time, use notepad, wordpad or my personal favourite, as it has a lot of advanced functions like reloading of files when they change, TextPad.