using System.Net;

        string[] GetIPaddresses(string computername)
        {
            string[] saddr = null;
            IPAddress[] addr = Dns.Resolve(computername).AddressList;

            if (addr.Length > 0)
            {
                saddr = new String[addr.Length];
                for (int i = 0; i < addr.Length; i++)
                    saddr[i] = addr[i].ToString();
            }
            return saddr;
        }

        

          
		public bool CheckIpAddr(string ipAddress)
		{
      IPAddress ip;
      return System.Net.IPAddress.TryParse(ipAddress, out ip);
		}
					
        

          
		public bool CheckIpAddr(string ipAddress)
		{
      string[] parts = ipAddress.Split('.');
      if (parts.Length != 4)
        return false;
      foreach(string part in parts)
      {
        byte n;
        if (!byte.TryParse(part, out n))
          return false;
      }
      return true;
		}
          
        

          
        static void Main(string[] args)
        {
            // Objet mail
            MailMessage msg = new MailMessage();
            // Expéditeur (obligatoire)
            msg.From = "expediteur@free.f";
            // destinataire (il en faut au moins un)
            msg.To = "atoi@free.fr;alui@free.fr";
            // destinataires en copie (facultatif)
            msg.Cc = "encoreatoi@free.fr";
            // Texte du mail (facultatif)
            msg.Body = "Bonjour\n" +
            "Ceci est le contenu du mail\n" +
            "A bientôt";
            // Fichier joint si besoin (facultatif)
            msg.Attachments.Add(new MailAttachment(@"c:\fichierjoint.txt", MailEncoding.UUEncode));
            // Serveur SMTP
            SmtpMail.SmtpServer = "smtp.nerim.fr";
            // Envoi du mail
            SmtpMail.Send(msg);
        }

        

          
        //...
        using System.Net;
        using System.Net.Mail;
        //...

        [STAThread]
        static void Main(string[] args)
        {
            // Objet mail
            MailMessage msg = new MailMessage();

            // Expéditeur (obligatoire). Notez qu'on peut spécifier le nom
            msg.From = new MailAddress("john.doe@gmail.com", "John Doe");
            
            // Destinataires (il en faut au moins un)
            msg.To.Add(new MailAddress("jack.sparrow@blackpearl.com", "Jack Sparrow"));
            msg.To.Add(new MailAddress("agent.smith@matrix.com", "Agent Smith"));

            // Destinataire(s) en copie (facultatif)
            msg.Cc.Add(new MailAddress("wonder.woman@superhero.com", "Wonder Woman"));

            // Texte du mail (facultatif)
            msg.Body = "Bonjour\n" +
            "Ceci est le contenu du mail\n" +
            "A bientôt";
            
            // Fichier joint si besoin (facultatif)
            msg.Attachments.Add(new Attachment(@"c:\fichierjoint.txt"));

            // Envoi du message SMTP
            SmtpClient client = new SmtpClient("smtp.gmail.com", 587);
            client.EnableSsl = true;
	        client.Credentials = new NetworkCredentials("john.doe@gmail.com", "mon_mot_de_passe");
            
            // Envoi du mail
            client.Send(msg);
        }

        

<configuration>
  <system.net>
    <mailSettings>
      <smtp deliveryMethod="network">
        <network
          host="smtp.domaine.com"
          port="25"
          userName="mon_login"
          password="mon_mot_de_passe"
        />
      </smtp>
    </mailSettings>
  </system.net>
</configuration>

          
	using System.Net;
	using System.IO;

        

          
        private void button1_Click(object sender, System.EventArgs e)
        {
            HttpWebResponse HttpWResponse = null;
            StreamReader sr = null;
            try
            {
                HttpWebRequest HttpWRequest = (HttpWebRequest)WebRequest.Create(textBox1.Text);
                HttpWResponse = (HttpWebResponse)HttpWRequest.GetResponse();
                sr = new StreamReader(HttpWResponse.GetResponseStream());
                richTextBox1.Text = sr.ReadToEnd();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                if (HttpWResponse != null)
                    HttpWResponse.Close();
                if (sr != null)
                    sr.Close();
            }
        }

        

          
		using System.Runtime.InteropServices;

		// Déclaration de l'API
		[DllImport("wininet.dll")]
		public extern static bool InternetGetConnectedState( out int Description, int ReservedValue ) ;

		// Utilisation de l'API
		public static bool IsConnected()
		{
			int Desc ;
			return InternetGetConnectedState( out Desc, 0 ) ;
		}

        

          
      // Pinguer un machine
      Ping monPing = new Ping();
      PingReply Reply = monPing.Send("192.168.1.31");

      Console.WriteLine("Statut du ping : {0}", Reply.Status);
      
        

          
      // Nom de la machine
      String NomMachine = Dns.GetHostName();

      // Récupération de la liste des IP de la machine
      IPHostEntry InfoIps = Dns.GetHostEntry(NomMachine);
      IPAddress[] MesIp = InfoIps.AddressList;

      foreach (IPAddress CurrentIp in MesIp)
          Console.WriteLine("Ip : {0}", CurrentIp.ToString());
      
        

          
class Program
{
    [StructLayout(LayoutKind.Sequential)]
    public struct _SERVER_INFO_100
    {
        internal int sv100_platform_id;
        [MarshalAs(UnmanagedType.LPWStr)]
        internal string sv100_name;
    }

    [DllImport("Netapi32", SetLastError = true), SuppressUnmanagedCodeSecurityAttribute]
    public static extern int NetApiBufferFree(IntPtr pBuf);

    [DllImport("Netapi32", CharSet = CharSet.Auto, SetLastError = true), SuppressUnmanagedCodeSecurityAttribute]
    public static extern int NetServerEnum(
        string ServerNane,
        int dwLevel,
        ref IntPtr pBuf,
        int dwPrefMaxLen,
        out int dwEntriesRead,
        out int dwTotalEntries,
        int dwServerType,
        string domain,
        out int dwResumeHandle
        );

    const int LVL_100 = 100;
    const int MAX_PREFERRED_LENGTH = -1;
    const int SV_TYPE_WORKSTATION = 1;
    const int SV_TYPE_SERVER = 2;

    /// <summary>
    /// Cette fonction est tirée d'une source trouvée ici => http://www.codeproject.com/cs/internet/ListNetworkComputers.asp
    /// </summary>
    public static string[] GetComputers()
    {
        ArrayList computers = new ArrayList();
        IntPtr buffer = IntPtr.Zero, tmpBuffer = IntPtr.Zero;
        int entriesRead, totalEntries, resHandle;
        int sizeofINFO = Marshal.SizeOf(typeof(_SERVER_INFO_100));

        try
        {
            int ret = NetServerEnum(null, LVL_100, ref buffer, MAX_PREFERRED_LENGTH, out entriesRead, out totalEntries, SV_TYPE_WORKSTATION | SV_TYPE_SERVER, null, out resHandle);
            if (ret == 0)
            {
                for (int i = 0; i < totalEntries; i++)
                {
                    tmpBuffer = new IntPtr((int)buffer + (i * sizeofINFO));

                    _SERVER_INFO_100 svrInfo = (_SERVER_INFO_100)Marshal.PtrToStructure(tmpBuffer, typeof(_SERVER_INFO_100));
                    computers.Add(svrInfo.sv100_name);
                }
            }
            else
                throw new Win32Exception(ret);
        }
        finally
        {
            NetApiBufferFree(buffer);
        }

        return (string[])computers.ToArray(typeof(string));
    }

    static void Main(string[] args)
    {
        string[] computers = GetComputers();

        foreach (string computer in computers)
        {
            Console.WriteLine(computer);
        }
        Console.Read();
    }
}
      
        

          
// Création de la requête
System.Net.WebRequest objWebRequest = System.Net.HttpWebRequest.Create("http://dotnet.developpez.com");
// Envoi de la requête au serveur
System.Net.WebResponse objWebResponse = objWebRequest.GetResponse();

// Stream pour récupérer le résultat
System.IO.StreamReader objStreamReader = null;

try
{
    // Récupération du résultat
    objStreamReader = new System.IO.StreamReader(objWebResponse.GetResponseStream());

    // Lecture du résultat
    textBox_Resultat.Text = objStreamReader.ReadToEnd();
}
catch
{ }
finally
{
    // Fermeture de la connexion
    if (objWebResponse != null)
        objWebResponse.Close(); 
}
        

          
    [SoapDocumentMethod(OneWay = true)]
    //[SoapRpcMethod(OneWay=true)]
    [WebMethod(Description = "Comment appeler une méthode Web sans attendre une réponse du serveur ?")]
    public void SaveToLog(string logEntry)
    {
        EventLog FaqLog = new EventLog("OneWayAttributeDemo");
        FaqLog.Source = "OneWayAttributeDemo";
        FaqLog.WriteEntry(logEntry, EventLogEntryType.Information);
    }