Cross-platform file name handling in .NET Core

Question

How to handle file name in System.IO classes in a cross-platform manner to make it work on Windows and Linux?

For example, I write this code that works

Answer 1

Windows using Backslash. Linux using Slash. Path.Combine set the right symbol :
Path.Combine Method - MSDN

Answer 2

You can also use Path.DirectorySeparatorChar as below:

 Console.WriteLine("..{0}Data{0}uploads{0}{{filename}}", Path.DirectorySeparatorChar);

Reference: MSDN

Answer 3

Of course forward slashes work fine - except when they don't. It is an older problem, but certainly LoadLibrary actually bit me in this regard. Please see https://stackoverflow.com/a/34708551/1318024 which discusses this. Even though we do expect Windows to handle path separators gracefully (which we do not expect for *nix!) it is best to use the path separator appropriate for the platform.

Answer 4

The original post is over a year old but I still ran into this issue. It seems to me like the use of dots in relative paths is also an issue.

A path like

".\\input\\mydata.csv" 

worked well on windows but not on unix. When changing the dot-notation for current directory to:

Path.GetFullPath(Directory.GetCurrentDirectory())

I had more success.

Answer 5

Lots of good answers. I would just like to add that one can avoid having to specify the directory separator character by using Path.Combine

Example with the file relatively located at ".\..\toto\app.config":

Path.Combine("..", "toto", "app.config");

Unfortunately, Path.Combine does not resolve a relative path to an absolute Path in .Net Core. Path.GetFullPath is here for that:

Path.GetFullPath(Path.Combine("..", "toto", "app.config"))

Answer 6

You can simply use slashes. Relative paths will work identically, and absolute paths can only be relative to the root of the main drive (as absolute paths starting with "c:" are not portable)