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

Here is a quick implementation that just loops through the list of strings and then compares the characters at the beginning of the strings trimming from the original string:

List list1 = new List();
list1.Add(@"c:\abc\pqr\tmp\sample\b.txt");
list1.Add(@"c:\abc\pqr\tmp\new2\c1.txt");
list1.Add(@"c:\abc\pqr\tmp\b2.txt");
list1.Add(@"c:\abc\pqr\tmp\b3.txt");
list1.Add(@"c:\abc\pqr\tmp\tmp2\b2.txt");

string baseDir = "";
foreach (var item in list1)
{
    if (baseDir == "")
        baseDir = System.IO.Path.GetDirectoryName(item);
    else
    {
        int index = 0;
        string nextDir = System.IO.Path.GetDirectoryName(item);
        while (index< baseDir.Length && index