CODEWITHSUNDEEP
c#filesystems
Earth Engine
Earth Engine

Reputation: 10436

Best way to check if a directory is a starting point of another path

I want to know how to implement the following:

Debug.Assert(PathStartsWith("C:\\dir1\\dir2\\dir3", "C:\\dir1") == true);
Debug.Assert(PathStartsWith("C:\\dir1\\dir2\\dir3", "C:\\dir2") == false);
Debug.Assert(PathStartsWith("C:\\dir1\\dir2\\dir3", "C:\\dir1\dir2") == true);

//not matching from start
Debug.Assert(PathStartsWith("C:\\dir1\\dir2\\dir3", "dir1") == false); 

//redundant slashes are ignored
Debug.Assert(PathStartsWith("C:\\dir1\\dir2\\dir3", "c:\\\\dir1") == true);

Do I have to do it myself (won't be too hard but there are a lot of cases to check, for example UNC paths, device paths, urls etc), or there are some system routine that can do this easily?

Upvotes: 0

Views: 197

Answers (1)

William
William

Reputation: 1875

I do not believe there is any built in capability for this in the BCL. If you are willing to use p/invoke, the shell provides a number of path functions.

See: PathIsSameRoot function

As a side note, none of the Win32 path functions will reliably tell if you two paths are equivalent. To do that, you'd need to create some kind of canonical path based on the Windows Object Manager namespace and then probably still take into account NTFS junction points, hard links and soft links (and probably more).

Even with that, you'd still have problems with network share UNC paths as a single server may have multiple names with no general way to reconcile them.

Upvotes: 1

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