how to extract common file path from list of file paths in c#

Question

What is the best way extract the common file path from the list of file path strings in c#?

Eg: I have a list 5 file paths in List variable, like below

c:\

Answer 1

The top answer fails for identical paths like e.g.:

string str1 = @"c:\dir\dir1\dir2\dir3";
string str2 = @"c:\dir\dir1\dir2\dir3";

This is better: Find common prefix of strings

however

.TakeWhile(s => s.All(d => d == s.First()))

should be

.TakeWhile(s =>
      {
          var reference = s.First();
          return s.All(d => string.Equals(reference, d, StringComparison.OrdinalIgnoreCase));
      })