C＃在指定目录和子目录中找到最新创建的* .txt文件？

Question

I have now tried everything but something is not working:

I need to find the newest Date Created *.txt file in my specified directory and sub-directories.

string tPath = "C:\MyDirectory";
string[] fDir = Directory.GetFiles(tPath, "*.txt",  SearchOption.AllDirectories); 
filePath = fDir[0];

Adding, the following leads to and compilation error:

string[] fDir = Directory.GetFiles(tPath, "*.txt",  SearchOption.AllDirectories).OrderByDescending(f => f.LastWriteTime).First();             

Error CS1061 'string' does not contain a definition for 'LastWriteTime' and no extension method 'LastWriteTime' accepting a first argument of type 'string' could be found

Im out of ideas, please help

Answer 1

First, Directory.GetFiles() is wildly inefficient for enumerating file system objects. Directory.EnumerateFileSystemEntries() does the same job in a significantly more optimal way.

Next, what GetFiles() (and EnumerateFileSystemEntries() , for that matter) return is a collection of full paths to file system objects, which is why your second snippet is failing to compile. Try something like

foreach(var fileInfo in Directory.EnumerateFileSystemEntries().Select(s => new FileInfo(s))

This might fail too (permissions, EnumerateFileSystemEntries() returning directory paths, etc.), but will get you going.

Answer 2

Thanks for the help, actually found the answer to my own question:

string tPath = "C:\MyDirectory";
filePath = Directory.EnumerateFiles(tPath, "*.txt", SearchOption.AllDirectories).OrderByDescending(File.GetCreationTime).First();

the difference was: OrderByDescending(File.GetCreationTime).First()

NOT OrderByDescending(f => f.GetCreationTime).First()

ps thanks for the tip about .enumeratefiles