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Check Your Internet Connection With C#

12. Mar, 2007 by admin 0 Comments

How to check if your computer is connected to the internet with C#. It's much more easier that other tutorials I've seen in other sites. In deed, we're going to use a simple API function InternetGetConnectedState, to return a boolean variable.

This function takes two arguments :

The first one is an integer used with out keyword, that means that after calling the function, the variable will contain an interger that describes the connection state ( use of a modem, use of a proxy, offline mode…). Note that you must refer to www.msdn.com for more information about that.
The second one is a reserved variable that must be set to 0.

In this tutorial, we'll create a class with a static function that returns true if connected and false if not, using our API function in private state.

Check this out :

using System ;
using System.Runtime ;
using System.Runtime.InteropServices ;

public class InternetCS
{

//Creating the extern function…
[DllImport("wininet.dll")]
private extern static bool InternetGetConnectedState( int out Description, int ReservedValue ) ;

//Creating a function that uses the API function…
public static bool IsConnectedToInternet( )
{

int Desc ;
return InternetGetConnectedState( out Desc, 0 ) ;

}