C#

public void FindDoc(string pathfile)
{
DirectoryInfo info = new DirectoryInfo(pathfile);
foreach (FileInfo f in info.GetFiles())
{
find(f);
}
foreach (DirectoryInfo d in info.GetDirectories())
{
foreach (FileInfo f in d.GetFiles())
{
find( f );
}
FindDoc(d.FullName);
}
}

public void FindDoc(string pathfile)
{
foreach (string d in Directory.GetDirectories(pathfile)) 
{
foreach (string f in Directory.GetFiles(d)) 
{
FileInfo info = new FileInfo(f);
find(info);
}
FindDoc(d);
}
}

private void GetFiles(DirectoryInfo directory, string searchPattern)
{
   foreach(DirectoryInfo subdirectory in directory.GetDirectories())
      GetFiles(subdirectory, searchPattern);

   
   foreach(FileInfo file in directory.GetFiles(searchPattern))
      fileList.Add(file);
}

using System;
using System.Runtime.InteropServices;
 
public class WindowsLogon
{
    public enum LogonType
    {
        Batch = 4,
        Interactive = 2,
        Network = 3,
        NetworkCleartext = 8,
        NewCredentials = 9,
        Service = 5,
        Unlock = 7,
    }
 
    public enum LogonProvider
    {
        Default = 0,
        WinNT35 = 1,
        WinNT40 = 2,
        WinNT50 = 3,
    }
 
    [DllImport("Advapi32.dll")]
    private static extern bool LogonUser(
        string lpszUserName,
        string lpszDomain,
        string lpszPassword,
        LogonType dwLogonType,
        LogonProvider dwLogonProvider,
        out IntPtr phToken);
 
    public static IntPtr LogonUser(
        string username, string password, string domain)
    {
        return LogonUser(username, password, domain, 
            LogonType.Network, LogonProvider.Default);
    }
 
    public static IntPtr LogonUser(
        string username, string password, string domain, 
        LogonType logonType, LogonProvider provider)
    {
        IntPtr ret = IntPtr.Zero;
        if (LogonUser(
            username, domain, password, 
            logonType, provider, out ret))
        {
            return ret;
        }
        else
            return IntPtr.Zero;
    }
 
    static void Main()
    {
        try
        {
            Console.Write("Username: ");
            string user = Console.ReadLine();
            Console.Write("Password: ");
            string password = Console.ReadLine();
 
            string domain = Environment.GetEnvironmentVariable("USERDOMAIN");
            Console.WriteLine("Domain: {0}", domain);
 
            IntPtr token = LogonUser(user, password, domain);
            if (IntPtr.Zero == token)
                Console.WriteLine("Logon failed!");
            else
                Console.WriteLine("Logon OK!");
 
        }
        catch(Exception ex)
        {
            Console.WriteLine(ex);
        }
    }
}

using System.IO;
...
void SaveToFile(Icon icon, string filename)
{
    using(FileStream stream = File.Open(filename,
        FileMode.OpenOrCreate,
        FileAccess.Write,
        FileShare.None))
    {
        icon.Save(stream);
        stream.Flush();
        stream.Close();
    }
}