Function InetIsOffline(Flag: Integer): Boolean; stdcall; external 'URL.DLL';

IF InetIsOffline(0) then ShowMessage('This computer is not connected to Internet!') else

 ShowMessage(You are connected to Internet!');

interface

 

Uses  Windows;

 

{ Flags for InternetGetConnectedState }

 

Const

  INTERNET_CONNECTION_MODEM      = 1;

  INTERNET_CONNECTION_LAN        = 2;

  INTERNET_CONNECTION_PROXY      = 4;

  INTERNET_CONNECTION_MODEM_BUSY = 8;

  winetdll = 'wininet.dll';

 

Function InternetGetConnectedState(lpdwFlags: LPDWORD; dwReserved: DWORD):BOOL; stdcall; external winetdll name 'InternetGetConnectedState';

 

implementation

 

Function InternetConnected: Boolean;

Var dwConnectionTypes: DWORD;

Begin

  dwConnectionTypes :=INTERNET_CONNECTION_MODEM +INTERNET_CONNECTION_LAN +INTRERNET_CONNECTION_PROXY;

  Result := InternetGetConnectedState(@dwConnectionTypes, 0);

End;

 

Хотя возможно через RAS API. Компоненты можно поискать на www.torry.net

 

[i]Kondakov[/i]

Я попробовал это на основе предложения Dmitriya Работает вроде. . Через Button  or Activate

 

unit Unit1;

interface

uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;

 

Const IC_Modem=1;

         IC_LAN= 2;

         IC_PROXY=3;

         IC_MODEM_BUSY=4;

         winetdll='wininet.dll';

 

Type Form1 = class(TForm)

           Button1: TButton;

           procedure CheckState(Sender: TObject);

 

End;

 

Var Form1: TForm1;

 

implementation

 

Function InternetGetConnectedState(lpdwFlags:LPDWORD; dwReserved: DWORD): BOOLEAN; stdcall; external winetdll name 'InternetGetConnectedState';

 

{$R *.DFM}

 

procedure TForm1.CheckState(Sender: TObject);

Var dwConnectionTypes: DWORD;

begin

 dwConnectionTypes:=IC_MODEM+IC_LAN+IC_PROXY;

 IF InternetGetConnectedState(@dwConnectionTypes,0) then ShowMessage('You are connected') else ShowMessage('No Connection');

end;

 

end.