Поиск папок в C#

Наверное, как-то так:

string FindFolderPath(string rootPath,string folderName){   
    var stack=new Stack<string>(Directory.GetDirectories(rootPath));    
    while(stack.Any())
    {
        var currentDir=stack.Pop();
        if (currentDir.Equals(folderName,StringComparison.OrdinalIgnoreCase)) return folderName;
        foreach (var dir in Directory.GetDirectories(currentDir))
        {
            stack.Push(dir);
        }
    }
    return null;
}