怎么样监测网络是否连接?

[phoenixluo]

我想做一个系统服务实时监测是否连接上网.该怎么做呀?

[CMIC]

Check Internet Connection by
http://www.c-sharpcorner.com/Code/2003/Aug/CheckInternetConnection.asp

[fanruinet]

public string NetStatus()
{
ManagementObjectCollection objects;
string status = "";
ManagementObjectSearcher searcher = new ManagementObjectSearcher();
searcher.Query.QueryString = "Select * From Win32_NetworkAdapter ";
objects = searcher.Get();
foreach(ManagementObject obj in objects)
{
foreach(PropertyData p in obj.Properties)
{
if(p.Name.Equals("NetConnectionStatus"))
{
if(p.Value!=null)
{
status = p.Value.ToString();
}
}
}
}
switch(status)
{
case "0":
return "Disconnected";
case "1":
return "Connecting ...";
case "2":
return "Connected";
case "3":
return "Disconnecting ...";
case "4":
return "Hardware not present";
case "5":
return "Hardware disabled";
case "6":
return "Hardware malfunction";
case "7":
return "Media disconnected";
case "8":
return "Authenticating";
case "9":
return "Authentication succeeded";
case "10":
return "Authentication failed";
default:
return "";
}
}