Find common prefix of strings

I am having 4 strings:

"h:/a/b/c"
"h:/a/b/d"
"h:/a/b/e"
"h:/a/c"

I want to find the common prefix for those strings, i.e. "h:/a". How to find that?

Usually I'd split the string with delimiter '/' and put it in another list, and so on.
Is there any better way to do it?

string[] xs = new[] { "h:/a/b/c", "h:/a/b/d", "h:/a/b/e", "h:/a/c" };

string x = string.Join("/", xs.Select(s => s.Split('/').AsEnumerable())
                              .Transpose()
                              .TakeWhile(s => s.All(d => d == s.First()))
                              .Select(s => s.First()));

with

public static IEnumerable<IEnumerable<T>> Transpose<T>(
    this IEnumerable<IEnumerable<T>> source)
{
    var enumerators = source.Select(e => e.GetEnumerator()).ToArray();
    try
    {
        while (enumerators.All(e => e.MoveNext()))
        {
            yield return enumerators.Select(e => e.Current).ToArray();
        }
    }
    finally
    {
        Array.ForEach(enumerators, e => e.Dispose());
    }
}

A short LINQy solution of mine.

var samples = new[] { "h:/a/b/c", "h:/a/b/d", "h:/a/b/e", "h:/a/e" };

var commonPrefix = new string(
    samples.First().Substring(0, samples.Min(s => s.Length))
    .TakeWhile((c, i) => samples.All(s => s[i] == c)).ToArray());

Just loop round the characters of the shortest string and compare each character to the character in the same position in the other strings. Whilst they all match keep going. As soon as one doesn't match then the string up to the current position -1 is the answer.

Something like (pseudo code)

int count=0;
foreach(char c in shortestString)
{
    foreach(string s in otherStrings)
    {
        if (s[count]!=c)
        {
             return shortestString.SubString(0,count-1); //need to check count is not 0 
        }
    }
    count+=1;
 }
 return shortestString;