Filtering folders from a list when using LINQ to sort to find the oldest file

Question

I am currently using the code below to get the oldest file in a given path. Recently a folder was created in that path that is quickly become the oldest "file". How can I modify the linq to filter directories and only report on files?

var fileInfo = new DirectoryInfo(path).GetFileSystemInfos();
var oldestFile = fileInfo.OrderBy(fi => fi.CreationTime).FirstOrDefault();

Answer 1

You could look only for files like below:

var oldestFile = fileInfo.Where(fi => fi is FileInfo)
                         .OrderBy(fi => fi.CreationTime)
                         .FirstOrDefault();

The method GetFileSystemInfos returns an array of System.IO.FileSystemInfo objects. This class is the base class of both FileInfo and DirectoryInfo objects, please have a look here. As it is mentioned in the previous link:

A FileSystemInfo object can represent either a file or a directory, thus serving as the basis for FileInfo or DirectoryInfo objects

So by passing the predicate

fi => fi is FileInfo

to the Where method above you get only the objects that represent files.