using System.Net; 

/// <summary>  /// 获得广播地址  /// </summary>  /// <param name="ipAddress">IP地址</param>  /// <param name="subnetMask">子网掩码</param>  /// <returns>广播地址</returns>  public static string GetBroadcast(string ipAddress, string subnetMask)  {

    byte[] ip = IPAddress.Parse(ipAddress).GetAddressBytes(); 

    byte[] sub = IPAddress.Parse(subnetMask).GetAddressBytes();

    // 广播地址=子网按位求反 再 或IP地址 

    for (int i = 0; i < ip.Length; i++)      {          ip[i] = (byte)((~sub[i]) | ip[i]);      }      return new IPAddress(ip).ToString();  }