网络检查是否连通？(50分)

请问各位高手，在DOS中Ping命令可以判断网络是否连通，但在Delphi中怎样判断一台计算机与其他计算机连通呢？

var
IPOpt:TIPOptionInformation;// IP Options for packet to send
FIPAddressWORD;
pReqData,pRevDataChar;
pIPEIcmpEchoReply;// ICMP Echo reply buffer
FSize: DWORD;
MyString:string;
FTimeOutWORD;
BufferSizeWORD;
begin
if ComboBox1.Text <> '' then
begin
FIPAddress := inet_addr(PChar(ComboBox1.Text));
FSize := 40;
BufferSize := SizeOf(TICMPEchoReply) + FSize;
GetMem(pRevData,FSize);
GetMem(pIPE,BufferSize);
FillChar(pIPE^, SizeOf(pIPE^), 0);
pIPE^.Data := pRevData;
MyString := 'Hello,World';
pReqData := PChar(MyString);
FillChar(IPOpt, Sizeof(IPOpt), 0);
IPOpt.TTL := 64;
FTimeOut := 4000;
IcmpSendEcho(hICMP, FIPAddress, pReqData, Length(MyString), @IPOpt, pIPE, BufferSize, FTimeOut);
try
if pReqData^ = pIPE^.Options.OptionsData^ then
begin
StatusShow.Lines.Add('IP Address bytes time(ms)');
StatusShow.Lines.Add(PChar(ComboBox1.Text) + ' ' +IntToStr(pIPE^.DataSize) + ' ' +IntToStr(pIPE^.RTT));
StatusShow.Lines.Add('Test Time：'+TimeToStr(now));
end;
except
begin
// StatusShow.Clear ;
StatusShow.Lines.Add('Address:'+ComboBox1.Text+' No Found;');
StatusShow.Lines.Add('Test Time：'+TimeToStr(now));
end;
// messagedlg('没有找到该IP地址!',mtinformation,[mbok],0);
end;
pIPE^.Phe := GetHostByAddr(@FIPAddress, 4, AF_INET);
if pIPE^.Phe <> Nil then HostName:=pIPE^.Phe^.h_name;
// caption:=hostname;

StatusShow.Lines.Add(hostname);
StatusShow.Lines.Add('');

FreeMem(pRevData);
FreeMem(pIPE);
end;
end;

======================================

或一个图型 PING 源代如下：

unit Unit1;

interface

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

type
PIPOptionInformation = ^TIPOptionInformation;
TIPOptionInformation = packed record
TTL: Byte;
TOS: Byte;
Flags: Byte;
OptionsSize: Byte;
OptionsData: PChar;
end;

PIcmpEchoReply = ^TIcmpEchoReply;
TIcmpEchoReply = packed record
Address: DWORD;
Status: DWORD;
RTT: DWORD;
DataSize: Word;
Reserved: Word;
Data: Pointer;
Options: TIPOptionInformation;
phe: pHostent;
end;
TIcmpCreateFile = function: THandle; stdcall;
TIcmpCloseHandle = function(IcmpHandle: THandle): Boolean; stdcall;
TIcmpSendEcho = function(IcmpHandle:THandle;
DestinationAddress: DWORD;
RequestData: Pointer;
RequestSize: Word;
RequestOptions: PIPOptionInformation;
ReplyBuffer: Pointer;
ReplySize: DWord;
Timeout: DWord
): DWord; stdcall;


TForm1 = class(TForm)
Panel1: TPanel;
pingedit: TEdit;
exebutton: TButton;
Label1: TLabel;
StatusShow: TMemo;
procedure FormCreate(Sender: TObject);
procedure exebuttonClick(Sender: TObject);
private
{ Private declarations }
hICMP: THANDLE;
IcmpCreateFile : TIcmpCreateFile;
IcmpCloseHandle: TIcmpCloseHandle;
IcmpSendEcho: TIcmpSendEcho;
public
{ Public declarations }
end;

var
Form1: TForm1;
HostName:string;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var
WSAData: TWSAData;
hICMPdll: HMODULE;
begin
wsastartup($101,wsadata);
hICMPdll := LoadLibrary('icmp.dll');
@ICMPCreateFile := GetProcAddress(hICMPdll, 'IcmpCreateFile');
@IcmpCloseHandle := GetProcAddress(hICMPdll, 'IcmpCloseHandle');
@IcmpSendEcho := GetProcAddress(hICMPdll, 'IcmpSendEcho');
hICMP := IcmpCreateFile;
StatusShow.Text := '';
statusshow.Align := alclient;
StatusShow.Lines.Add('目的IP地址 字节数 返回时间(毫秒)');
end;

procedure TForm1.exebuttonClick(Sender: TObject);
var
IPOpt:TIPOptionInformation;// IP Options for packet to send
FIPAddressWORD;
pReqData,pRevDataChar;
pIPEIcmpEchoReply;// ICMP Echo reply buffer
FSize: DWORD;
MyString:string;
FTimeOutWORD;
BufferSizeWORD;
begin
if PingEdit.Text <> '' then
begin
FIPAddress := inet_addr(PChar(PingEdit.Text));
FSize := 40;
BufferSize := SizeOf(TICMPEchoReply) + FSize;
GetMem(pRevData,FSize);
GetMem(pIPE,BufferSize);
FillChar(pIPE^, SizeOf(pIPE^), 0);
pIPE^.Data := pRevData;
MyString := 'Hello,World';
pReqData := PChar(MyString);
FillChar(IPOpt, Sizeof(IPOpt), 0);
IPOpt.TTL := 64;
FTimeOut := 4000;
IcmpSendEcho(hICMP, FIPAddress, pReqData, Length(MyString), @IPOpt, pIPE, BufferSize, FTimeOut);
try
if pReqData^ = pIPE^.Options.OptionsData^ then
begin
StatusShow.Lines.Add(PChar(PingEdit.Text) + ' ' +IntToStr(pIPE^.DataSize) + ' ' +IntToStr(pIPE^.RTT));
end;
except
messagedlg('没有找到该IP地址!',mtinformation,[mbok],0);
end;
pIPE^.Phe := GetHostByAddr(@FIPAddress, 4, AF_INET);
if pIPE^.Phe <> Nil then HostName:=pIPE^.Phe^.h_name;
caption:=hostname;
FreeMem(pRevData);
FreeMem(pIPE);
end;
end;


end.

用Indy下组件，一句话搞定。

能详细一点吗？

Program Files/Borland/Delphi6/Demos/Indy/PingGUI
有demo

请问ICS中有个PING的控件在哪下载？我找了好多次都找不到，请大哥们帮帮馒忙呀！

接受答案了.