How to programmatically select a network card connected to the Internet in .NET.

Question

I want to programmatically select a network card connected to the Internet. I need this to control how much traffic goes through the map. This is what I use to get instance names

var category = new PerformanceCounterCategory("Network Interface"); String[] instancenames = category.GetInstanceNames(); 

And this is how instancenames looks at my car

 [0] "6TO4 Adapter" [1] "Internal" [2] "isatap.{385049D5-5293-4E76-A072-9F7A15561418}" [3] "Marvell Yukon 88E8056 PCI-E Gigabit Ethernet Controller" [4] "isatap.{0CB9C3D2-0989-403A-B773-969229ED5074}" [5] "Local Area Connection - Virtual Network" [6] "Teredo Tunneling Pseudo-Interface" 

I want the solution to be reliable and work on other PCs, I would also prefer .NET. I found other solutions, but they seem more complicated for the purposes.

• Use C ++ or WMI
• Parsing netstat output

Is there anything else?

Thanks!

EDIT

Before voting, in order to close this question, please read it first and make sure that I have already mentioned some of the available solutions. I ask if there is anything else simpler and more reliable (i.e. NOT C ++, WMI, or parsing the output of a console application)

Answer 1

Ultimately, I use WMI and an external function call, I did not find a better solution. Here is my code if anyone is interested.

 using System; using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Linq; using System.Management; using System.Net; using System.Net.Sockets; using System.Runtime.InteropServices; using log4net; namespace Networking { internal class NetworkCardLocator { [DllImport("iphlpapi.dll", CharSet = CharSet.Auto)] public static extern int GetBestInterface(UInt32 DestAddr, out UInt32 BestIfIndex); private static ILog log = OperationLogger.Instance(); /// <summary> /// Selectes the name of the connection that is used to access internet or LAN /// </summary> /// <returns></returns> internal static string GetConnectedCardName() { uint idx = GetConnectedCardIndex(); string query = String.Format("SELECT * FROM Win32_NetworkAdapter WHERE InterfaceIndex={0}", idx); var searcher = new ManagementObjectSearcher { Query = new ObjectQuery(query) }; try { ManagementObjectCollection adapterObjects = searcher.Get(); var names = (from ManagementObject o in adapterObjects select o["Name"]) .Cast<string>() .FirstOrDefault(); return names; } catch (Exception ex) { log.Fatal(ex); throw; } } private static uint GetConnectedCardIndex() { try { string localhostName = Dns.GetHostName(); IPHostEntry ipEntry = Dns.GetHostEntry(localhostName); IPAddress[] addresses = ipEntry.AddressList; var address = GetNeededIPAddress(addresses); uint ipaddr = IPAddressToUInt32(address); uint interfaceindex; GetBestInterface(ipaddr, out interfaceindex); return interfaceindex; } catch (Exception ex) { log.Fatal(ex); throw; } } private static uint IPAddressToUInt32(IPAddress address) { Contract.Requires<ArgumentNullException>(address != null); try { byte[] byteArray1 = IPAddress.Parse(address.ToString()).GetAddressBytes(); byte[] byteArray2 = IPAddress.Parse(address.ToString()).GetAddressBytes(); byteArray1[0] = byteArray2[3]; byteArray1[1] = byteArray2[2]; byteArray1[2] = byteArray2[1]; byteArray1[3] = byteArray2[0]; return BitConverter.ToUInt32(byteArray1, 0); } catch (Exception ex) { log.Fatal(ex); throw; } } private static IPAddress GetNeededIPAddress(IEnumerable<IPAddress> addresses) { var query = from address in addresses where address.AddressFamily == AddressFamily.InterNetwork select address; return query.FirstOrDefault(); } } }