File deletion using a thread in C#

Question

My thread cannot delete PDF files. When I debug this solution, the file is deleting. In service mode, it is not deleting.

This is my sample code:

Thread Worker = new Thread(new ThreadStart(Start)); //Main Function
Worker.Start();

public void Start()
{
    string text=PDFToText(@"C:\1.pdf");
    File.Delete(@"C:\1.pdf");
}

private string PDFToText(string filename) // My PDF reader function
{
    PDDocument doc = PDDocument.load(filename);
    PDFTextStripper stripper = new PDFTextStripper();
    string text = stripper.getText(doc);
    doc.close();
    return text;
}

Where is the problem?

I guess this is not an error with deleting a file using a thread, but currently the file is in use when the thread called it. — roybalderama, May 09 '13 at 08:39
Could you add a Catch Exception Message to see if an error occurs? — Sean, May 09 '13 at 08:40
So it silently fails to delete the file? That's a little bizarre. Have you looked in the system event log to see if the service threw an Exception? — Adrian, May 09 '13 at 08:41

Moo-Juice · Accepted Answer · 2013-05-09T09:02:57.867

What is possibly happening is that something (probably the API you are using) has a lock on the file, preventing the delete.

When you do this in debug and step through, because you're stepping through it at a "slow" pace, the lock has been released, and the file is successfully deleted.

You should put the deletion code in a retry loop with an exception handler, which sleeps for a second or so and then tries again, giving OS a chance to relinquish the lock.

Another thing to consider is that, assuming you are running this as a service when in production, the service is running under a different user-account than when you debug it through visual studio (assuming you are not attaching to the service - it's hard to tell here). Check that the account the service is running under has permissions to delete the file in the first place.

File deletion using a thread in C#

1 Answers1