再次请教联机问题？

Question

我的机器是在局域网内，请问有什么好的办法判断是否连机了呢？急

Answer 1

用来判断计算机是否连接到internet 的.里面是通过ping 来判断的, 可以修改来判两台机是否连接
type
  PIPOptionInformation = ^TIPOptionInformation;
  TIPOptionInformation = packed record
    TTL: Byte;
    TOS: Byte;
    Flags: Byte;
    OptionsSize: Byte;
    OptionsData: PChar;
  end;
  type PIcmpEchoReply = ^TIcmpEchoReply;
  TIcmpEchoReply = packed record
    Address: DWord;
    Status: DWord;
    RTT: DWord;
    DataSize:Word;
    Reserved: Word;
    Data: Pointer;
    Options: TIPOptionInformation;
  end;
  TIcmpCreateFile = function: THandle; stdcall;
  TIcmpCloseHandle = function(IcmpHandle: THandle): Boolean; stdcall;
  TIcmpSendEcho = function(IcmpHandle:THandle;
                           DestinationAddress:DWord;
                           RequestData: Pointer;
                           RequestSize: DWord;
                           RequestOptions: PIPOptionInformation;
                           ReplyBuffer: Pointer;
                           ReplySize: DWord;
                           Timeout: DWord): DWord; stdcall;type
 private
    { Private declarations }
        hICMP: THANDLE;
  IcmpCreateFile : TIcmpCreateFile;
  IcmpCloseHandle:TIcmpCloseHandle;
  IcmpSendEcho: TIcmpSendEcho;
  public
   { Public declarations }
    hICMPdll: HMODULE;  end;implementation
var
  IPOpt:TIPOptionInformation;
  FIPAddress:DWORD;
  pReqData,pRevData:PChar;
  pIPE:PIcmpEchoReply;
  FSize: DWORD;
  MyString:string;
  FTimeOut:DWORD;
  BufferSize:DWORD;
  Date1,Date3,Date4:TDateTime;
  TableName1,
  TableName3,Tablename4:string;
  Num1,Num2,Num3,Num4:integer;
  i:integer;
  DateStr1:String;
begin
hICMPdll := LoadLibrary('icmp.dll');
@ICMPCreateFile:= GetProcAddress(hICMPdll, 'IcmpCreateFile');
@IcmpCloseHandle := GetProcAddress(hICMPdll, 'IcmpCloseHandle');
@IcmpSendEcho := GetProcAddress(hICMPdll, 'IcmpSendEcho');
hICMP := IcmpCreateFile;
FIPAddress:=inet_addr(PChar('169.254.3.253'));//IP地址  改为对方计算机IP
FSize:=80;
BufferSize:=SizeOf(TICMPEchoReply)+FSize;
GetMem(pRevData,FSize);
GetMem(pIPE,BufferSize);
FillChar(pIPE^, SizeOf(pIPE^), 0);
pIPE^.Data := pRevData;
MyString := 'Argen Ping32 Sending Message.';
pReqData := PChar(MyString);
FillChar(IPOpt, Sizeof(IPOpt), 0);
IPOpt.TTL:= 64;
FTimeOut :=500;
IcmpSendEcho(hICMP, FIPAddress, pReqData, Length(MyString),@IPOpt, pIPE,
        BufferSize, FTimeOut);
try
try
if pReqData^ = pIPE^.Options.OptionsData^ then
showmeesage('目标到达');
except
Messagebox(self.handle,'目标不可到','Ping32',64)
end;
finally
FreeMem(pRevData);
FreeMem(pIPE);
end;
end;end.