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c#windows-servicesfilesystemwatcher

"Parameter is incorrect" when moving file with Windows Service

I've written a Windows Service in C#/VS2008/.NET3.5 that monitors some FTP directories with FileSystemWatchers and moves the files out to another location for processing. I noticed today that it throws errors stating "The parameter is incorrect" soon after the service has started up, but if we wait a few minutes the file gets copied without incident. I saw that the error message is often related to incorrect permissions, but I verified permissions on the directories (target and source) were correct and as I said the file move works just a few minutes later.

Here's a snippet of the code that gets called when the file is finished copying into the FTP directory being monitored:

//found the correct source path
string targetDir = dir.TargetDirectory;
string fileName = Path.GetFileName(e.FullPath);

errorlocation = "move file";
string targetFilePath = Path.Combine(targetDir, fileName);
if (File.Exists(targetFilePath))
{
    File.Delete(targetFilePath);
}
File.Move(e.FullPath, Path.Combine(targetDir, fileName));

dir refers to and object with information about the directory the file was being loaded into. e is the FileSystemEventArgs. Targetdir is grabbed from the directory's settings in a custom configuration block in the app.config that tells the service where to copy the new files to.

I didn't include the code here, but I know it's failing on the File.Move (last line above) due to some EventLog entries I made to trace the steps.

Any idea as to why the move fails soon after the service startup, but works fine later?

Basic overview of the process in case it sheds some light: external vendors FTP us a number of files each day. When the file comes in, my code identifies who the file is coming from based off the FTP directory and then loads settings to pass on to SSIS jobs that will parse and save the files. There are maybe a dozen or so directories being monitored right now each of which has its own configuration setting for the SSIS job. Is it possible that the system gets confused as startup and just need some time to populate all the settings? Each source directory does have its own FileSystemWatcher on it.

Thanks for your help.

Solution

  • I'm marking this answered because the problem went away. We haven't changed anything in the code, but it now works immediately after restart. The best theory we have is: since I posted this, the client I was working for moved offices and as part of the migration a lot of system and network policies were updated and server setting tweaked for the new environment. It's likely one (or more) of those changes fixed this issue.

    Further support for this theory: prior to the move my development VM could not run web browsers. (I'd click to load the browser and it wouldn't work, sometimes it would appear briefly in Task Manager and then disappear.) After the office move, this problem no longer occurs.

    So it was likely some network setting somewhere that caused issues. Sorry I can't be more specific.