How do I create a random image name in C#?

Question

When I add a picture I want it to create a new random file name because if you add a picture with the same name it will just overwrite.

Answer 1

The is a built-in method Path.GetRandomFileName. It returns a random folder name or file name.

The GetRandomFileName method returns a cryptographically strong, random string that can be used as either a folder name or a file name. Unlike GetTempFileName, GetRandomFileName does not create a file. When the security of your file system is paramount, this method should be used instead of GetTempFileName.

If you want to use your extension (e.g. .jpg instead of generated), you could use another helper method Path.ChangeExtension:

string extension = ".jpg";
string fileName = Path.ChangeExtension(
    Path.GetRandomFileName(),
    extension
);

System.IO.Path.GetRandomFileName gets a file name that is guaranteed to be unique.

Answer 2

As you want to save pictures, you could just use a GUID as the filename:

string filename = Path.Combine(Path.GetTempPath(), Guid.NewGuid() + ".jpg");

I always do it this way when I need another file extension than .tmp (which files get when you create them via GetTempFileName).
Of course you could create the files via GetTempFileName and then rename them, but then you have to check again if a file with the new name exists...

Answer 3

You could generate a Guid and use that for your file name. Although this would mean that the files are not human readable and have no information as to what the content is.