unit1.pas

判断本机是否上网,在delphi7下开发,用到wininet控件.

unit Unit1;

interface

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

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

var
  Form1: TForm1;

implementation

{$R *.dfm}

const
    INTERNET_CONNECTION_MODEM = 1;   // 通过modem连接上网
    INTERNET_CONNECTION_LAN = 2;  // 通过局域网连接上网
    INTERNET_CONNECTION_PROXY = 4;  // 通过代理连接上网
    INTERNET_CONNECTION_MODEM_BUSY = 8;  // modem忙，未能连接上网

procedure TForm1.Button1Click(Sender: TObject);
var
dwConnectionTypes: DWORD;
Is_connected:Bool;
begin
 dwConnectionTypes := INTERNET_CONNECTION_MODEM+ INTERNET_CONNECTION_LAN+ INTERNET_CONNECTION_PROXY;
    Is_connected :=InternetGetConnectedState(@dwConnectionTypes, 0);
    if Is_connected then
    begin
        if (dwConnectionTypes and INTERNET_CONNECTION_MODEM) = INTERNET_CONNECTION_MODEM then
          edit1.Text:='通过Modem连接上网';
        if (dwConnectionTypes and INTERNET_CONNECTION_LAN) = INTERNET_CONNECTION_LAN then
          edit1.Text:='通过局域网连接上网';
        if (dwConnectionTypes and INTERNET_CONNECTION_PROXY) = INTERNET_CONNECTION_PROXY then
          edit1.Text:='通过代理连接上网';
    end;
    end;


end.