[.net] Relative paths...
Author
Hi,
What I would like to know is if there is a function (in the FileSystem namespace?) that can take a filename and different path and make the filename relative to this path. For example, taking:
C:\Documents and Settings\My Name\My Documents\file.txt
and
C:\Documents and Settings\Test Directoryand generate the filename:
..\..\Test Directory\file.txt
Hopefully there is a built in function for this, but I just cannot find one. If not, I'd be appreciative to hear any suggestions on efficient and reliable ways to do this...
Thanks in advance,
Alex
This simple algorithm should work
Path1 = "C:\A\B\C\D\" <-- iam here
Path2 = "C:\A\B\E\"
1. Tokenize Paths
Path1_tokens = {"C:","A","B","C","D"}
Path2_tokens = {"C:","A","B","E"}
2. Delete equal Strings before first unequal
Path1_tokens = {"C","D"}
Path2_tokens = {"E"}
3. Replace Path1_tokens with ".."
Path1_tokens = {"..",".."}
Path2_tokens = {"E"}
Result = Path1_tokens + Path2_tokens = "\..\..\E\"
Path1 = "C:\A\B\C\D\" <-- iam here
Path2 = "C:\A\B\E\"
1. Tokenize Paths
Path1_tokens = {"C:","A","B","C","D"}
Path2_tokens = {"C:","A","B","E"}
2. Delete equal Strings before first unequal
Path1_tokens = {"C","D"}
Path2_tokens = {"E"}
3. Replace Path1_tokens with ".."
Path1_tokens = {"..",".."}
Path2_tokens = {"E"}
Result = Path1_tokens + Path2_tokens = "\..\..\E\"
I don't think such a function exists in the framework.
But Macoy's solution is correct.
Note that the Tokenizing could simply be done with one call to the Split function, if you know that all separator are '\'.
You also have to check that both path have the same drive as root, otherwise no relative path from one to the other exists.
But Macoy's solution is correct.
Note that the Tokenizing could simply be done with one call to the Split function, if you know that all separator are '\'.
You also have to check that both path have the same drive as root, otherwise no relative path from one to the other exists.
Author
thanks a lot for both your replies :) macoy, i thought of a similar method to that but your specific one seems perfect...
Check out:
System.IO.Directory
System.IO.DirectoryInfo (does what you want)
System.IO.File
System.IO.FileInfo
System.IO.Directory
System.IO.DirectoryInfo (does what you want)
System.IO.File
System.IO.FileInfo
Author
sounds like the sort of namespace i'd want, but i can't find the exact function. :S if you could specify exactly how i should use it in the context of my problem, that's be great :D
Author
ok, i guess there's no built in method, that's ok. i'll just use macoy's method then and it should work nicely :).
Author
Here's my code for the solved problem:
thanks again for the help :) though it was a bit trickier than i thought to implement...
'Get relative filenameProtected Function GetRelativeFilename(ByVal filename As String, ByVal relativePath As String) As String Dim sPath1 As String = IO.Path.GetDirectoryName(filename) Dim sPath2 As String = IO.Path.GetDirectoryName(relativePath) Dim sPath1Tokens As String() = sPath1.Split(IO.Path.DirectorySeparatorChar) Dim sPath2Tokens As String() = sPath2.Split(IO.Path.DirectorySeparatorChar) Dim iTokenIndex As Integer, iTokenUB As Integer Dim bPathChanged As Boolean Dim sPathBack As String = "" Dim sPathForward As String = "" If IO.Path.GetPathRoot(sPath1).ToLower() <> IO.Path.GetPathRoot(sPath2).ToLower() Then Return filename End If iTokenUB = Math.Max(sPath1Tokens.GetUpperBound(0), sPath2Tokens.GetUpperBound(0)) For iTokenIndex = 0 To iTokenUB If iTokenIndex <= sPath1Tokens.GetUpperBound(0) Then If bPathChanged Then sPathBack &= ".." & IO.Path.DirectorySeparatorChar End If ElseIf Not bPathChanged Then bPathChanged = True End If If iTokenIndex <= sPath2Tokens.GetUpperBound(0) Then If bPathChanged Then sPathForward &= sPath2Tokens(iTokenIndex) & IO.Path.DirectorySeparatorChar End If ElseIf Not bPathChanged Then bPathChanged = True sPathBack &= ".." & IO.Path.DirectorySeparatorChar End If If Not bPathChanged Then If sPath1Tokens(iTokenIndex).ToLower() <> sPath2Tokens(iTokenIndex).ToLower() Then bPathChanged = True sPathBack &= ".." & IO.Path.DirectorySeparatorChar sPathForward &= sPath2Tokens(iTokenIndex) & IO.Path.DirectorySeparatorChar End If End If Next Return sPathBack & sPathForward & IO.Path.GetFileName(filename)End Functionthanks again for the help :) though it was a bit trickier than i thought to implement...
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