Function to shrink file path to be more human readable

Nasreddine answer was nearly correct. Just specify StringBuilder size, in your case:

[DllImport("shlwapi.dll", CharSet = CharSet.Auto)]
static extern bool PathCompactPathEx(
                       [Out] StringBuilder pszOut, 
                       string szPath, 
                       int cchMax, 
                       int dwFlags);

static string PathShortener(string path, int length)
{
    StringBuilder sb = new StringBuilder(length + 1);
    PathCompactPathEx(sb, path, length, 0);
    return sb.ToString();
}

That looks less human readable to me. Anyway, I don't think there is such a function. split it on the \ character and just keep the first two slots and the last two slots and you have it.

Something like this, although that code is not very elegant

  string[] splits = path.Split('\\');
  Console.WriteLine( splits[0] + "\\" + splits[1] + "\\...\\" + splits[splits.Length - 2] + "\\" +  splits[splits.Length - 1]);

Jeff Atwood posted a solution to this on his blog and here it is :

[DllImport("shlwapi.dll", CharSet = CharSet.Auto)]
static extern bool PathCompactPathEx([Out] StringBuilder pszOut, string szPath, int cchMax, int dwFlags);

static string PathShortener(string path, int length)
{
    StringBuilder sb = new StringBuilder();
    PathCompactPathEx(sb, path, length, 0);
    return sb.ToString();
}

It uses the unmanaged function PathCompactPathEx to achieve what you want.