unit1.pas

< Delphi网络通信协议分析与应用实现>>一书的源代码。

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Edit1: TEdit;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
var
   Types : Integer;
begin
{    CopyRight (C) Bowman      }
{    [e-mail]    }
   Types := INTERNET_CONNECTION_MODEM +
            INTERNET_CONNECTION_LAN +
            INTERNET_CONNECTION_PROXY;
   //check 3 conditions together
    if InternetGetConnectedState(@types, 0) then
       Edit1.Text := 'your pc is Online now'
    else
       Edit1.Text := 'your pc is offline now';
end;

end.