Difference between File.Replace and (File.Delete+File.Move) in C#

Question

Today I ran into a strange problem: Since a year and several versions / tests of the application the following code has been used successfully to replace a file with an other.

File.Replace(path + ".tmp", path, null);

This has worked locally and also with UNC paths (network shares). But today I got the following error when I used this code to replace a file on a UNC path (local still works):

The process cannot access the file because it is being used by another process

When I use the following code instead of the above, it works:

File.Delete(path);
File.Move(path + ".tmp", path);

So my questions:

• What is the difference between the two code snippets?
• Could it be that Microsoft have changed the way 'File.Replace' works?

I'm using .Net Framework 4.0 with Visual Studio 2010.

Thanks in advance.

Answer 1

According to MSDN on File.Replace

File.Replace will throw an exception when...

• the destination file is missing.
• source and destination are on different volumes

Which File.Delete, File.Move won't.

Answer 2

Here's the MSDN article on File.Replace()

Creating a backup of the original appears to be the difference.