How to copy a file while it is being used by another process

Question

Is it possible to copy a file which is being using by another process at the same time?

I ask because when i am trying to copy the file using the following code an exception is raised:

 System.IO.File.Copy(s, destFile, true); 

The exception raised is:

The process cannot access the file 'D:\temp\1000000045.zip' because it is being used by another process.

I do not want to create a new file, I just want to copy it or delete it. Is this possible?

Answer 1

An Example (note: I just combined two google results, you may have to fix minor errors ;))

The important part is the FileShare.ReadWrite when opening the FileStream.

I use a similar code to open and read Excel documents while excel is still open and blocking the file.

using (var inputFile = new FileStream(     "oldFile.txt",     FileMode.Open,     FileAccess.Read,     FileShare.ReadWrite)) {     using (var outputFile = new FileStream("newFile.txt", FileMode.Create))     {         var buffer = new byte[0x10000];         int bytes;          while ((bytes = inputFile.Read(buffer, 0, buffer.Length)) > 0)         {             outputFile.Write(buffer, 0, bytes);         }     } } 

Answer 2

To create a copy of a file that is read- and/or write-locked by another process on Windows, the simplest (and probably only) solution is to use the Volume Shadow Copy Service (VSS).

The Volume Shadow Copy Service is complex and difficult to call from managed code. Fortunately, some fine chaps have created a .NET class library for doing just this. Check out the Alpha VSS project on CodePlex: http://alphavss.codeplex.com.

EDIT

As with many of the projects on CodePlex, Alpha VSS has migrated to GitHub. The project is now here: https://github.com/alphaleonis/AlphaVSS.