[C#]判断计算机是否处于连网(联网)状态

if ( SystemInformation.Network )

{
MessageBox.Show("该计算机已经联网");
}
else

{
MessageBox.Show("该计算机尚未联网");
}

/// <summary>
/// 获得IP地址
/// </summary>
/// <returns>string类型的IP地址</returns>
public string GetIPAddress()
{
string text = string.Empty;
string result;
try
{
IPAddress[] addressList = Dns.GetHostEntry(Dns.GetHostName()).AddressList;
IPAddress[] array = addressList;
for (int i = 0; i < array.Length; i++)
{
IPAddress iPAddress = array[i];
if (!iPAddress.IsIPv6SiteLocal)
{
text = iPAddress.ToString();
}
}
if (string.IsNullOrEmpty(text))
{
throw new Exception("Can not get this computer ip address.");
}
result = text;
}
catch (Exception ex)
{
throw new Exception("GetIPAddress Exception: " + ex.Message);
}
return result;
}

public void GetIPAddress(ref string host,ref string ip)
{
try
{
host = Dns.GetHostName().ToUpper();
IPAddress[] addressList = Dns.GetHostEntry(Dns.GetHostName()).AddressList;
IPAddress[] array = addressList;
for (int i = 0; i < array.Length; i++)
{
IPAddress iPAddress = array[i];
if (!iPAddress.IsIPv6SiteLocal)
{
ip = iPAddress.ToString();
}
}
if (string.IsNullOrEmpty(host))
{
throw new Exception("Can not get this computer name.");
}
if (string.IsNullOrEmpty(ip))
{
throw new Exception("Can not get this computer ip address.");
}
}
catch(Exception ex)
{
throw new Exception("GetIPAddress Exception:" + ex.Message);
}
}