Copy only new or modified files/directories in C#

Aubrey Love

I know this has probably been done and discussed umpteen times, but I can’t find the answer I am looking for.

I am trying to create a simple “directory/file copy" console application in C#.

What I need is to copy all folders and files (keeping the original hierarchy) from one drive to another, like from drive C:\Data to drive E:\Data.

However, I only want it copy any new or modified folders and files. If the folder or file on the destination drive is newer than the one on the source drive, then it does not copy.

Here is the code I have tried, but it’s not working. Any suggestions? Thank you.

class Copy
{
public static void CopyDirectory(DirectoryInfo source, DirectoryInfo destination)
{
if (!destination.Exists)
{
destination.Create();
}
// Copy files.
FileInfo[] files = source.GetFiles();
FileInfo[] destFiles = destination.GetFiles();
foreach (FileInfo file in files)
foreach (FileInfo fileD in destFiles)
// Copy only modified files
if (file.Exists)
{
if (file.LastWriteTime > fileD.LastWriteTime)
{
file.CopyTo(Path.Combine(destination.FullName,
file.Name), true);
}
}
// Copy all new files
else
if (!fileD.Exists)
{
file.CopyTo(Path.Combine(destination.FullName, file.Name), true);
}
// Process subdirectories.
DirectoryInfo[] dirs = source.GetDirectories();
foreach (DirectoryInfo dir in dirs)
{
// Get destination directory.
string destinationDir = Path.Combine(destination.FullName, dir.Name);
// Call CopyDirectory() recursively.
CopyDirectory(dir, new DirectoryInfo(destinationDir));
}
}
}

5 Replies

Know the answer? Post it — somebody with the same question will find it here.

Aubrey Love7y ago
Okay, I found the solution to my problem.

Just after the second “foreach” in the “if (file.Exists)” replace the “file.exists” with “file.Name.Equals(fileD.Name)” and the program works perfect.
0
Aubrey Love7y ago
Thanks for the advice. I tried using the "FileSystemWatcher" class and though I don't know much about it yet, I read what I could on MSDN and in a C# book.
I got it to work, but only if it is actively running. As I mentioned, I don't want it running 24/7.
I only want to run this app once a day and generate a daily report.

Does anyone have any ideas why my code (above) is not working?

Thanks.
0
Amit Gupta7y ago
That's what I had mentioned, FileSystemWatcher class will be best suited for your needs. You can do the stuffs like overwrite/skip in those events.

You can hide your application and monitor the directory you wanted. It uses async monitoring, so it cannot have a negative impact on performance on your system.

Good Luck!
0
Aubrey Love7y ago
Thanks for the quick reply. However -
That's close to what I want, but I don't want it to monitor the folder. I am going to setup a job in a program called OpCon that schedules the program to run at certain times of the day.
I was just looking for a way to copy all new files from source to destination and if the destination has the same file, then copy from the source (overwriting the destination file) but only if the source file is newer than the destination file. Otherwise, skip.
0
Amit Gupta7y ago
Hey

The answer you required is FileSystemWatcher class, just command the class to monitor the particular directory or its subdirectories. You will get the event if there is any new/modified/deleted event.

Choose according to your requirement

Good Luck!
0