Problem concerning the File.GetLastWriteTime

[AwAk3e]

I seem to be getting very strange behaviour and it is obviously a result of my programming. What I was aiming for was an incremental backup software for a college project. The form being designed and a recursive file copying method I have done.

Now to keep the form from freezing when the file copying operation is taking place I have used the backgroundWorker control in the graphical design view and I am using this to run the File Copying in a separate thread and that works.

The FileCopying method looks like so:

public void FullCopy(string sConfigLocation, string sourceFolder, string destFolder, string sDriveName, object iniFile)
        {
            if (!Directory.Exists(destFolder))
                Directory.CreateDirectory(destFolder);
        
            //System.Windows.Forms.ToolTip ToolTip1 = new System.Windows.Forms.ToolTip();
            string[] files = Directory.GetFiles(sourceFolder);
            foreach (string file in files)
            {
                string name = Path.GetFileName(file);
                string dest = Path.Combine(destFolder, name);
                DateTime WriteTime = File.GetLastWriteTimeUtc(dest);
                backgroundWorker1.ReportProgress(0, name);
                try
                {
                    File.Copy(file, dest, true);
                }
                catch (Exception ex)
                {
                    MessageBox.Show("The file " + file + " could not be copied because of error, '" + ex + "'");
                }
                IniFunctions.WriteToIni(sConfigLocation, sDriveName, file, WriteTime.ToString(), iniFile); 
            }
            string[] folders = Directory.GetDirectories(sourceFolder);
            foreach (string folder in folders)
            {
                string name = Path.GetFileName(folder);
                string dest = Path.Combine(destFolder, name);
                FullCopy10(sConfigLocation, folder, dest, sDriveName, iniFile);
            }
        }

However when looking into the INI file all the times are, '01/01/1601 00:00:00'. I have no idea why. If I then call this after the method:

 public void confirmTimeCheck(string sConfigLocation, string sourceFolder, string destFolder, string sDriveName, object iniFile)
        {
            string[] files = Directory.GetFiles(sourceFolder);
            foreach (string file in files)
            {
                string name = Path.GetFileName(file);
                string dest = Path.Combine(destFolder, name);
                DateTime WriteTime = File.GetLastWriteTimeUtc(dest);
                IniFunctions.WriteToIni(sConfigLocation, sDriveName, file, WriteTime.ToString(), iniFile);
            }
            string[] folders = Directory.GetDirectories(sourceFolder);
            foreach (string folder in folders)
            {
                string name = Path.GetFileName(folder);
                string dest = Path.Combine(destFolder, name);
                confirmTimeCheck(sConfigLocation, folder, dest, sDriveName, iniFile);
            }
        }

Which is just the exact same thing taking out the FileCopying operations it now works fine. The times are correct. :|

So it seems that for some reason when I'm calling FileCopy operations in the same method as retrieving the timestamp, the timestamp will come back as, '01/01/1601 00:00:00' or as the same time the confirmTimeCheck method retrieves.

So this is a problem now as I need to check the current LastWriteTime with one stored in the INI files so I can decide which ones I can update.

Does anyone know why the File.GetLastWriteTime is not working properly in that method? Perhaps a problem with it being in a different thread? The backgroundWorker method is:

public void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            CopyObject a = e.Argument as CopyObject;
            FullCopy(a.sConfigLocation, a.sourceFolder, a.destFolder, a.sDriveName, a.iniFile);
            confirmTimeCheck(a.sConfigLocation, a.sourceFolder, a.destFolder, a.sDriveName, a.iniFile)
            e.Result("Complete");
        }

I hope someone can shed some light on this, thanks in advance.

[memeloo]

check the paths, msdn says that:
File.GetLastWriteTimeUtc

If the file described in the path parameter does not exist, this method returns 12:00 midnight, January 1, 1601 A.D. (C.E.) Coordinated Universal Time (UTC).

very strange. I would expect an exception and not such a strange result.

[AwAk3e]

.. Thank you for the hint on the paths. I can't believe I was so idiotic to put the DESTINATION of where the file is going to be. :| As I was giving it the destination it was checking where the file would be after the copy operation. :| That explains why it works the second time and not the first time.

Very silly mistake yet I still would of missed it if it wasn't for you're Tip on the path . Thanks Memeloo, I appreciate it greatly. Thanks.