How to rename a file in .NET?

Question

Using System.IO.File or another .NET class, what is the best way to rename a file?

I want to be able to rename files on local drives or on network locations.

If using System.IO.File, is Move the best way?

Answer 1

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Alternatives

System.IO.File.Move

You can rename a file with System.IO.File.Move like this:

var sourcePath = @"C:\folder\oldname.txt";
var destinationPath = @"C:\folder\newname.txt";
File.Move(sourcePath, destinationPath);

You may be interested in keeping the same location and just change the name of the file. Sure that can be done:

var sourcePath = @"C:\folder\oldname.txt";
var newName = "newname.txt";
var directory = Path.GetDirectoryName(sourcePath);
var destinationPath = Path.Combine(directory, newName);
File.Move(sourcePath, destinationPath);

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System.IO.FileInfo.MoveTo

You can also use System.IO.FileInfo.MoveTo:

var sourcePath = @"C:\folder\oldname.txt";
var destinationPath = @"C:\folder\newname.txt";
FileInfo info = new FileInfo(sourcePath);
info.MoveTo(destinationPath);

Note: You can also build the destination path as shown above.

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"Hand move"

Evidently you can always open the existing file, create a new one with the desired name... copy the contests from the old to the new one, and finally delete the old one. This will work given you have write access, although dates and security info (owner of the file, etc...) will not be preserved.

You can see an example of that at the accepted solution of How to write contents of one file to another file?.

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Notes

Note 1: Others alternatives include: Microsoft.VisualBasic.FileSystem.Rename and Microsoft.VisualBasic.FileIO.FileSystem.RenameFile.

Both Microsoft.VisualBasic.FileSystem.Rename and System.IO.File.Move are equivalent, they do parameter checks, permissions checks and error handling around MoveFile from kernel32.

Regarding Microsoft.VisualBasic.FileIO.FileSystem.RenameFile, it will rename files in the same folder given the full path and the new name (similar to what I present above to build the destination path), and then fall back to MoveFile from kernel32.

In a similar fashion System.IO.FileInfo.MoveTo will call MoveFile from kernel32.

Note 2: It should also be noted that you cannot find Microsoft.VisualBasic from Mono. That means that System.IO.File.Move and System.IO.FileInfo.MoveTo are the only portable options.

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It is all MoveFile.

As mentioned above all those methods will fallback to MoveFile from kernel32. MoveFile will work for any mounted drive on the system (even network drives), although it should not be used to move from a volume to another. In that case it will be necessary to copy the file to the destination and remove the old file.

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The best alternative

Since the Microsoft.VisualBasic.FileSystem.Rename and Microsoft.VisualBasic.FileIO.FileSystem.RenameFile may not be used in other operating systems as they are not ported by Mono, I'll discard those.

So, we are left with System.IO.File.Move and System.IO.FileInfo.MoveTo. Between those System.IO.File.Move has less overhead because it doesn't have to maintain the state of the FileInfo object. Other than that they will work the same... so, if you are already using FileInfo use System.IO.FileInfo.MoveTo otherwise System.IO.File.Move.

And so, System.IO.File.Move is the best option to rename files in .NET! (They didn't give us a whacky API).

Celebrate!