unit1.pas

检测某台机器是否在网上,检测某台机器是否在网上

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Edit1: TEdit;
    Button1: TButton;
    Memo1: TMemo;
 function FindComputer(ComputerName:String):Boolean;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}
function FindComputer(ComputerName:String):Boolean;
var
  WSAData:TWSAData;
  HostEnt:THostEnt;
begin
  Result:=True;   //默认返回值为真
  WSAStartup(2,WSAData);   //初始化动态连接库Ws2_32.dll
  HostEnt:=GetHostByName(PChar(ComputerName));    //调用api函数GetHostByName
  if HostEnt=nil then
    Result:=False;   //如果HostEnt为空则表明没有找到目标机器
    WSACleanup;    //释放动态连接库Ws2_32.dll所占用的内存
end;


procedure TForm1.Button1Click(Sender: TObject);
begin
  if FindComputer(Edit1.Text)=true then
    Memo1.Lines.Add (Edit1.text+'在局域网上!')
  else
    Memo1.Lines.Add (Edit1.text+'不在局域网上!');
end;

end.