unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, WinInet, Vcl.StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

const
    INTERNET_RAS_INSTALLED          = $10;
    INTERNET_CONNECTION_OFFLINE     = $20;
    INTERNET_CONNECTION_CONFIGURED  = $30;

implementation

{$R *.dfm}

function internetConnected : boolean;
var
    dwConnectionTypes : DWORD;
begin
    if(InternetGetConnectedState(@dwConnectionTypes, 0)) then
    begin
       if((dwConnectionTypes and INTERNET_CONNECTION_MODEM)      <> 0)then Result := True;
       if((dwConnectionTypes and INTERNET_CONNECTION_LAN)        <> 0)then Result := True;
       if((dwConnectionTypes and INTERNET_CONNECTION_PROXY)      <> 0)then Result := True;
       if((dwConnectionTypes and INTERNET_CONNECTION_MODEM_BUSY) <> 0)then Result := True;
       if((dwConnectionTypes and INTERNET_RAS_INSTALLED)         <> 0)then Result := True;
       if((dwConnectionTypes and INTERNET_CONNECTION_OFFLINE)    <> 0)then Result := True;
       if((dwConnectionTypes and INTERNET_CONNECTION_CONFIGURED) <> 0)then Result := True;
    end
    else
    begin
        Result := False;
    end;

end;

procedure TForm1.Button1Click(Sender: TObject);
begin
    if internetConnected then
        showmessage('connected')
    else
        showmessage('disconnected');
end;

end.