怎样用程序知道局域网某台机器是否开机，比如说局域网里有一台机器叫server,怎么知道它开没开机？还有就是局域网里都有哪些计算机已经开机？ (100分)

怎样知道局域网某台机器是否开机，还有就是局域网里都有哪些计算机已经开机？

一个一个的ping

通过程序获得局域网内的机器名:
type
PnetResourceArr = ^TNetResource;

implementation
procedure GetServerList(List:TStrings);
Type
{$H+}
PMyRec = ^MyRec;
MyRec = Record
dwScope : Integer;
dwType : Integer;
dwDisplayType : Integer;
dwUsage : Integer;
LocalName : String;
RemoteName : String;
Comment : String;
Provider : String;
End;
{H-}
Var
NetResource : TNetResource;
TempRec : PMyRec;
Buf : Pointer;
Count,
BufSize,
Res : DWORD;
lphEnum : THandle;
p : PNetResourceArr;
i,
j : SmallInt;
NetworkTypeList : TList;
begin
// Result := False;

NetworkTypeList := TList.Create;
List.BeginUpdate;
List.Clear;
GetMem(Buf, 8192);
Try
Res := WNetOpenEnum(RESOURCE_GLOBALNET, RESOURCETYPE_DISK, RESOURCEUSAGE_CONTAINER, Nil,lphEnum);
If Res <> 0 Then Raise Exception(Res);
Count := $FFFFFFFF;
BufSize := 8192;
Res := WNetEnumResource(lphEnum, Count, Pointer(Buf), BufSize);
If Res = ERROR_NO_MORE_ITEMS Then Exit;
If (Res <> 0) Then Raise Exception(Res);
P := PNetResourceArr(Buf);
For I := 0 To Count - 1 Do
Begin
New(TempRec);
TempRec^.dwScope := P^.dwScope;
TempRec^.dwType := P^.dwType ;
TempRec^.dwDisplayType := P^.dwDisplayType ;
TempRec^.dwUsage := P^.dwUsage ;
TempRec^.LocalName := StrPas(P^.lpLocalName);
TempRec^.RemoteName := StrPas(P^.lpRemoteName);
TempRec^.Comment := StrPas(P^.lpComment);
TempRec^.Provider := StrPas(P^.lpProvider);
NetworkTypeList.Add(TempRec);
Inc(P);
End;
Res := WNetCloseEnum(lphEnum);
If Res <> 0 Then Raise Exception(Res);
For J := 0 To NetworkTypeList.Count-1 Do
Begin
TempRec := NetworkTypeList.Items[J];
NetResource := TNetResource(TempRec^);
Res := WNetOpenEnum(RESOURCE_GLOBALNET, RESOURCETYPE_DISK, RESOURCEUSAGE_CONTAINER, @NetResource,lphEnum);
If Res <> 0 Then Raise Exception(Res);
While true Do
Begin
Count := $FFFFFFFF;
BufSize := 8192;
Res := WNetEnumResource(lphEnum, Count, Pointer(Buf), BufSize);
If Res = ERROR_NO_MORE_ITEMS Then Break;
If (Res <> 0) Then Raise Exception(Res);
P := PNetResourceArr(Buf);
For I := 0 To Count - 1 Do
Begin
List.Add(P^.lpRemoteName);
Inc(P);
End;
End;
End;
Res := WNetCloseEnum(lphEnum);
If Res <> 0 Then Raise Exception(Res);
//Result := True;
Finally
FreeMem(Buf);
NetworkTypeList.Destroy;
End;
List.EndUpdate;
end;

procedure GetUserList(fServer:string;List:TStrings);
Var
NetResource : TNetResource;
Buf : Pointer;
Count,
BufSize,
Res : DWord;
Ind : Integer;
lphEnum : THandle;
Temp : PNetResourceArr;
Begin


List.Clear;
GetMem(Buf, 8192);
Try
FillChar(NetResource, SizeOf(NetResource), 0);
NetResource.lpRemoteName := @fServer[1];
NetResource.dwDisplayType := RESOURCEDISPLAYTYPE_SERVER;
NetResource.dwUsage := RESOURCEUSAGE_CONTAINER;
NetResource.dwScope := RESOURCETYPE_DISK;
Res := WNetOpenEnum(RESOURCE_GLOBALNET, RESOURCETYPE_DISK, RESOURCEUSAGE_CONTAINER, @NetResource,lphEnum);
If Res <> 0 Then Exit;
While True Do
Begin
Count := $FFFFFFFF;
BufSize := 8192;
Res := WNetEnumResource(lphEnum, Count, Pointer(Buf), BufSize);
If Res = ERROR_NO_MORE_ITEMS Then Exit;
If (Res <> 0) then Exit;
Temp := PNetResourceArr(Buf);
For Ind := 0 to Count - 1 do
Begin
List.Add(Temp^.lpRemoteName + 2); { Add all the network usernames to List StringList }
Inc(Temp);
End;
End;
Res := WNetCloseEnum(lphEnum);
If Res <> 0 Then Raise Exception(Res);
// Result := True;
Finally
FreeMem(Buf);
End;
End;

这程序是网上来的，我整理了一个，就变成现在这样了。
procedure oncreate;
begin GetServerList(Listbox1.Items);end;
procedure Listbox1.Onclick
begin
GetUserList(Listbox1.Items[Listbox1.ItemIndex],Listbox2.Items);
end;
**************************************
获得网上邻居列表的程序
程序如下：
var
i : Integer;
ErrCode : Integer;
NetRes : Array[0..1023] of TNetResource;
EnumHandle : Thandle;
EnumEntries : Dword;
BufferSize : Dword;
ComputerIP,ComputerName:String;
begin
//try
With NetRes[0] do begin
dwScope :=RESOURCE_GLOBALNET;
dwType :=RESOURCETYPE_ANY;
dwDisplayType :=RESOURCEDISPLAYTYPE_DOMAIN;
dwUsage :=RESOURCEUSAGE_CONNECTABLE;
lpLocalName :=NIL;
lpRemoteName :=NIL;
lpComment :=NIL;
lpProvider :=NIL;
end;
{ get net root }
ErrCode:=WNetOpenEnum(
RESOURCE_GLOBALNET,
RESOURCETYPE_ANY,
RESOURCEUSAGE_CONTAINER,
@NetRes[0],
EnumHandle
);

If ErrCode=NO_ERROR then begin
EnumEntries:=1;
BufferSize:=SizeOf(NetRes);
ErrCode:=WNetEnumResource(EnumHandle,EnumEntries,@NetRes[0],BufferSize);
WNetCloseEnum(EnumHandle);
ErrCode:=WNetOpenEnum(
RESOURCE_GLOBALNET,
RESOURCETYPE_ANY,
RESOURCEUSAGE_CONNECTABLE,
@NetRes[0],
EnumHandle
);
EnumEntries:=1024;
BufferSize:=SizeOf(NetRes);
ErrCode:=WNetEnumResource(
EnumHandle,
EnumEntries,
@NetRes,
BufferSize
);

for i:=0 to 1023 do
if NetRes.lpRemoteName='' then Exit
else begin
ComputerName:=Copy(NetRes.lpRemoteName,3,Length(NetRes.lpRemoteName)-2);
ComputerIP:=GetIP(ComputerName);
ShowMessage('计算机名' + NetRes.lpRemoteName + chr(13)
+ '计算机说明:' + NetRes.lpComment + chr(13)
+ 'IP地址:' + ComputerIP);
end;
end;
*************
请问怎样获取所有能访问的网上邻居中的计算机名称列表？
通过Windows Shell API
用SHGetSpecialFolderLocation获得Neighborhood的PIDL，然后将一个IShellFolder接
口绑定到这个PIDL，再然后就可以用这个接口的EnumObjects函数枚举其中的对象了。
因我不会Delphi，所以不知道用Delphi应该具体如何做，下面一段C++代码列出了"我
的电脑"下的所有项目(我的计算机没有安装网络邻居，所以用这个代替，方法应该是
一样的)

#include <stdio.h>
#include <iostream.h>
#include <comdef.h>
#include <windows.h>
#include <shellapi.h>
#include <shlobj.h>
#include <shlguid.h>
#include <shlwapi.h>

void _inline error(){ cerr<<"ERROR!"<<endl; _exit(1); }

void main(int argc, char* argv[])
{
IMallocPtr pMalloc;
IShellFolderPtr pShellFolder,pFolder;
LPITEMIDLIST pidl;
IEnumIDListPtr pEnum;
HRESULT hr;
STRRET Name;
ULONG celtFetched;

SHGetMalloc(&amp;pMalloc);

if (!SUCCEEDED(SHGetDesktopFolder(&amp;pShellFolder)))
error();
if (!SUCCEEDED(SHGetSpecialFolderLocation(NULL,CSIDL_DRIVES,&amp;pidl)))
error();
pShellFolder->BindToObject(pidl,NULL,IID_IShellFolder,(LPVOID*)&amp;pFolder);

hr=pFolder->EnumObjects(NULL,SHCONTF_FOLDERS|SHCONTF_NONFOLDERS|
SHCONTF_INCLUDEHIDDEN,&amp;pEnum);

while ((hr = pEnum->Next (1, &amp;pidl, &amp;celtFetched)) != S_FALSE &amp;&amp;
celtFetched == 1)
{
hr = pFolder->GetDisplayNameOf (pidl, SHGDN_NORMAL , &amp;Name);
if (FAILED (hr))
{
error();
break;
}
printf("%s/n",Name.cStr);
}

if (!pidl)
pMalloc->Free(pidl);
}

**************
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, ComCtrls, ImgList, ExtCtrls, ToolWin;

type
TForm1 = class(TForm)
ImageList1: TImageList;
ToolBar1: TToolBar;
ToolButton1: TToolButton;
Panel1: TPanel;
ResourceTree: TTreeView;
Splitter1: TSplitter;
ResourceList: TListView;
Panel2: TPanel;
lbScope: TLabel;
lbType: TLabel;
lbDisplayType: TLabel;
lbUsage: TLabel;
lbLocalName: TLabel;
lbRemoteName: TLabel;
lbComment: TLabel;
lbProvider: TLabel;
ToolButton2: TToolButton;
procedure Button1Click(Sender: TObject);
procedure ResourceTreeChange(Sender: TObject; Node: TTreeNode);
procedure ToolButton2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
function AddTreeItem(nr:NETRESOURCE;node:TTreeNode):TTreeNode;
function EnumNetWorkResource(lpnrNetResource;node:TTreeNode):Boolean;
procedure ConnectResource(pnrNetResource);
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

{ TForm1 }
function GetLastErrorText:string;
var
dwSizeWORD;
lpszTemp:LPSTR;
begin
dwSize:=512;
lpszTemp:=nil;
try
GetMem(lpszTemp,dwSize);
FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM or FORMAT_MESSAGE_ARGUMENT_ARRAY,
nil,GetLastError,LANG_NEUTRAL,lpszTemp,dwSize,nil);
finally
Result:=StrPas(lpszTemp);
FreeMem(lpszTemp);
end;
end;

function TForm1.EnumNetWorkResource(lpnrNetResource;node:TTreeNode):Boolean;
var
nr:NetResource;
hEnum:THandle;
lpnrLocal: PNETRESOURCE;
cbBufferWORD;
cEntries,dwEnumResultWORD;
i:Integer;
LocalNode:TTreeNode;
begin
Result:=False;
cbBuffer:=163840;
cEntries:=$ffffffff;
lpnrLocal:=nil;
if(WNetOpenEnum(RESOURCE_GLOBALNET,
RESOURCETYPE_ANY,
0,
lpnr,
hEnum)<>NO_ERROR)then
begin
ShowMessage('Open enum error,node='+lpnr^.lpRemoteName);
ShowMessage(GetLastErrorText);
Result:=False;
Exit;
end;
try
repeat
lpnrLocal:=PNetResource(GlobalAlloc(GPTR,cbBuffer));
dwEnumResult:=WNetEnumResource(hEnum,
cEntries,
lpnrLocal,
cbBuffer);
if(dwEnumResult=NO_ERROR)then
begin
for i:=0 to cEntries-1 do
begin
nr:=(PNetResource(PChar(lpnrLocal)+sizeOf(NetResource)*i))^;
LocalNode:=AddTreeItem(nr,node);
if(RESOURCEUSAGE_CONTAINER=
nr.dwUsage and RESOURCEUSAGE_CONTAINER)then
begin
if(not EnumNetWorkResource(@nr,LocalNode))then
begin
ShowMessage('Error enum,Parent='+lpnr^.lpRemoteName);
ShowMessage(GetLastErrorText);
end;
end;
end;
end;
until (dwEnumResult=ERROR_NO_MORE_ITEMS);
if(dwEnumResult=ERROR_NO_MORE_ITEMS)then
Result:=True;
Except
GlobalFree(Cardinal(lpnrLocal));
WNetCloseEnum(hEnum);
Raise;
end;
GlobalFree(Cardinal(lpnrLocal));
WNetCloseEnum(hEnum);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
EnumNetWorkResource(nil,ResourceTree.Items[0]);
end;

function TForm1.AddTreeItem(nr: NETRESOURCE; node: TTreeNode): TTreeNode;
var
pnrNetResource;
begin
GetMem(pnr,SizeOf(NetResource));
pnr^:=nr;
Result:=ResourceTree.Items.AddChildObject(node,nr.lpRemoteName,pnr);
if(nr.dwUsage=RESOURCEUSAGE_CONTAINER)then
Result.ImageIndex:=0
else Result.ImageIndex:=1;
end;

procedure TForm1.ResourceTreeChange(Sender: TObject; Node: TTreeNode);
var
pnrNetResource;
begin
pnr:=PNetResource(Node.Data);
if(pnr=nil)then Exit;
case pnr^.dwScope of
RESOURCE_CONNECTED:
lbScope.Caption:='Connetted';
RESOURCE_GLOBALNET:
lbScope.Caption:='GlobalNet';
RESOURCE_REMEMBERED:
lbScope.Caption:='Remembered';
else
lbScope.Caption:='else scope:'+IntToStr(pnr^.dwScope);
end;



case pnr^.dwType of
RESOURCETYPE_DISK:
lbType.Caption:='Disk';
RESOURCETYPE_PRINT:
lbType.Caption:='Printer';
else
lbType.Caption:=IntToStr(pnr^.dwType);
end;

case pnr^.dwDisplayType of
RESOURCEDISPLAYTYPE_DOMAIN:
lbDisplayType.Caption:='Domain';
RESOURCEDISPLAYTYPE_GENERIC:
lbDisplayType.Caption:='Generic';
RESOURCEDISPLAYTYPE_SERVER:
lbDisplayType.Caption:='Server';
RESOURCEDISPLAYTYPE_SHARE:
lbDisplayType.Caption:='Shared';
else
lbDisplayType.Caption:='else type:'+IntToStr(pnr^.dwDisplayType);
end;

case pnr^.dwUsage of
RESOURCEUSAGE_CONTAINER:
lbUsage.Caption:='Container';
RESOURCEUSAGE_CONNECTABLE:
lbUsage.Caption:='Connectable';
else
lbUsage.Caption:='else Usage:'+IntToStr(pnr^.dwUsage);
end;

lbLocalName.Caption:=pnr^.lpLocalName;
lbRemoteName.Caption:=pnr^.lpRemoteName;
lbComment.Caption:=pnr^.lpComment;
lbProvider.Caption:=pnr^.lpProvider;

//ConnectResource(pnr);
end;

procedure TForm1.ConnectResource(pnr: PNetResource);
begin
if((pnr^.dwUsage and RESOURCEUSAGE_CONNECTABLE)
=RESOURCEUSAGE_CONNECTABLE)then
begin
{ if(WNetAddConnection2(pnr^,PChar(''),'wuwei',0)<>NO_ERROR)then
ShowMessage(GetLastErrorText);}
if(WNetAddConnection(pnr^.lpRemoteName,'','h:')<>NO_ERROR)then
ShowMessage(GetLastErrorText);
end;
end;

procedure TForm1.ToolButton2Click(Sender: TObject);
var
pNetResource;
begin
p:=PNetResource(ResourceTree.Selected.Data);
ConnectResource(p);
end;

end.

*******
查询局域网中NT服务器的计算机名
You should use API function

NET_API_STATUS NetServerEnum(
LPWSTR servername,
DWORD level,
LPBYTE *bufptr,
DWORD prefmaxlen,
LPDWORD entriesread,
LPDWORD totalentries,
DWORD servertype,
LPWSTR domain,
LPDWORD resume_handle
);

ping最简单了

大侠，详细一点吧！

好长啊，看晕了啊！

//给你一断PING的代码，希望有帮助


it myping;

interface

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

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

PIcmpEchoReply = ^TIcmpEchoReply;
TIcmpEchoReply =
record
Address: DWORD;
Status: DWORD;
RTT: DWORD;
DataSize:Word;
Reserved: Word;
Data: Pointer;
Options: TIPOptionInformation;
end;

function IcmpCreateFile():THandle;stdcall external 'ICMP.dll';
function IcmpCloseHandle(Handle:THandle):Boolean;stdcall external 'ICMP.dll';
function IcmpSendEcho(Handle:THandle;DestAddrWORD;
RequestData: Pointer;RequestSize: Word;RequestOptions: PIPOptionInformation;
ReplyBuffer: Pointer;ReplySize: DWORD;Timeout: DWORD): DWORD;stdcall external 'ICMP.dll';
procedure ValidCheck();
procedure FreeWinsock();
function Ping(IPAddr:String;TimeOut:Word):String;

Const
{ Exception Message }
SInitFailed = 'Winsock version error';
SInvalidAddr = 'Invalid IP Address';
SNoResponse = 'No Response';
STimeOut = 'Request TimeOut';

type
TForm1 = class(TForm)
Button1: TButton;
MemoResult: TMemo;
Label1: TLabel;
Label2: TLabel;
Editaddr: TEdit;
procedure Button1Click(Sender: TObject);
procedure FormCreate(Sender: TObject);



private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
hICMP:THandle;

implementation

{$R *.DFM}


procedure ValidCheck();
var
WSAData:TWSAData;
begin
//initiates use of WS2_32.DLL
if (WSAStartup(MAKEWORD(2,0),WSAData)<>0) then
raise Exception.Create(SInitFailed);
hIcmp:=IcmpCreateFile();
if hICMP=INVALID_HANDLE_VALUE then
raise Exception.Create('Create ICMP Failed');
end;
procedure FreeWinsock();
begin
IcmpCloseHandle(hIcmp);
WSACleanUP;
end;

function Ping(IPAddr:String;TimeOut:Word):String;
var
IPOpt:TIPOptionInformation;// IP Options for packet to send
FIPAddressWORD;
pReqData,pRevDataChar;
pIPEIcmpEchoReply;// ICMP Echo reply buffer
FSize: DWORD;
MyString:string;
FTimeOutWORD;
BufferSizeWORD;
temp:Integer;
pIPAddrchar;
begin
//get ip
GetMem(pIPAddr,Length(IPAddr)+1);
ZeroMemory(pIPAddr,Length(IPAddr)+1);
StrPCopy(pIPAddr,IPAddr);
//calc
FIPAddress := inet_addr(pIPAddr);
//free it
FreeMem(pIPAddr);
//valid check
if FIPAddress=INADDR_NONE then
begin
result:=SInvalidAddr;//Exit
exit;
end;
// WSAAsyncGetHostByAddr()
//package size
FSize := 40;
BufferSize := SizeOf(TICMPEchoReply) + FSize;
GetMem(pRevData,FSize);
GetMem(pIPE,BufferSize);
//prepare data
FillChar(pIPE^, SizeOf(pIPE^), 0);
pIPE^.Data := pRevData;
MyString := 'Ping Digital Data';
pReqData := PChar(MyString);
FillChar(IPOpt, Sizeof(IPOpt), 0);
//max delieve geteway
IPOpt.TTL := 64;
//time out
FTimeOut := TimeOut;
//go!!!
temp:=IcmpSendEcho(hICMP,//dll handle
FIPAddress,//target
pReqData,//data
Length(MyString),//data length
@IPOpt,//addree of ping option
pIPE,//
BufferSize,//pack size
FTimeOut);//timeout value
//check result
if temp=0 then
begin
Result:='Ping Addr:'+IPAddr+' '+SNoResponse;
exit;
end;
if pReqData^ = pIPE^.Options.OptionsData^ then
begin
//show result
Result:=('Reply from:'+PChar(IPAddr) + ' '
+'bytes:'+IntToStr(pIPE^.DataSize) + ' '
+'tims:'+IntToStr(pIPE^.RTT)+ 'ms '
+'TTL:'+intToStr(pIPE^.Options.TTL));
end;
//clear memory
FreeMem(pRevData);
FreeMem(pIPE);
end;

多人接受答案了。