SOCARs TechBlog Informatics tips & tricks

[.NET] Relative path

Below is a quick and dirty implementation of solution for how to get relative path to file from a folder

Problem1:

Path1 (base): C:\data\my_path
Path2 (target): C:\some_other\folder\data\file.txt
Result: ..\..\some_other\folder\data\file.txt

Problem2:
Path1 (base): C:\data\path
Path2 (target): C:\data\path\somedata\file.txt
Result: .\somedata\file.txt

Solution:

public static string getRelativePath(String baseDirectory, string destinationFile)
 {
   List<String> _from = new List<String>(baseDirectory.Split('\\'));
   List<String> _dest = new List<String>(destinationFile.Split('\\'));

   if (_from[0].ToLower() != _dest[0].ToLower() || _dest.Count==0 || _from.Count==0)
   {
     return destinationFile; //Not same disk
   }

   int lvl = 0;

   for(int i=0; i<_from.Count; i++)
   {

    if (_from[i].ToLower() != _dest[i].ToLower())
    {
     break;
    }

    lvl++;
   }

   for (int j = 0; j < lvl; j++)
   {
    _from.RemoveAt(0);
    _dest.RemoveAt(0);
   }

   String _resultPath = "";
   if (_from.Count == 0) //the file is in higher folder
   {
    _resultPath += ".\\";
    for (int i = 0; i < _dest.Count; i++)
    {
     _resultPath += _dest[i];
     if (i + 1 < _dest.Count)
       _resultPath += "\\";
    }

   }
   else
   {

     for (int i = 0; i < _from.Count; i++)
     {
      _resultPath += "..\\";
     }

     for (int i = 0; i < _dest.Count; i++)
     {
      _resultPath += _dest[i];
      if (i + 1 < _dest.Count)
        _resultPath += "\\";
     }
   }
   return _resultPath;
 }