Get full path with lower case file extension

Question

Hello
I have this string path:
C:\Users\Admin\Downloads\AbCd.PdF
Want to have:
C:\Users\Admin\Downloads\AbCd.pdf
Only the extension part needs to be converted to lower case, so:

Path.Combine(Path.GetDirectoryName(input), Path.GetFileNameWithoutExtension(input), Path.GetExtension(input).ToLowerInvariant)

And I get:
C:\Users\Admin\Downloads\AbCd.pdf

What's the story behind that backslash before extension?
And what's the safest culture invariant way to do this?
The path or file name might have non-ASCII characters.

Answer 1

I think that you should write something like this (in VB):

Path.ChangeExtension(input, Path.GetExtension(input).ToLowerInvariant)

or

Path.Combine(Path.GetDirectoryName(input), Path.GetFileNameWithoutExtension(input) & Path.GetExtension(input).ToLowerInvariant)

Path.Combine concatenates path elements (e.g. folder names) using '\' if required. It does not interprete the last argument as extension; it believes it is a folder.

Answer 2

What backslash before the extension? When you call Path.GetExtension it'll return .PDF. If you then call ToLower or ToLowerInvariant then it returns .pdf. If you want to take the current culture into account when lowercasing then use ToLower. If you are normalizing the value (like we often do with paths and keysthen useToLowerInvariant`.