Solved

a problem about API

Posted on 2001-07-06
4
164 Views
Last Modified: 2010-04-06
I  used a api function GetVolumeInformation to get the volume serial number of a cd. and I found that I can not get the same value in the win98 os and win2000 os . why!!!
my code is below
procedure TForm1.Button1Click(Sender: TObject);
var
 dw1,dw2:dword;
 p:pDWORD;
begin
  try
    getmem(p,255);
    getvolumeinformation('g:\',nil,0,p,dw1,dw2,nil,0);
    edit1.Text:=inttostr(p^);
  finally
    freemem(p);
  end;
end;

I get two different edit1.text in win98 and win2000. but in fact they should be the same value.

who can help me to solve the problem

sincerely yours
lovedelphi

0
Comment
Question by:lovedelphi
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 7

Accepted Solution

by:
Motaz earned 100 total points
ID: 6261282
Try this solution:

Drop a Button, Label and  a MediaPlayer component. Make sure that MMSYstem is included in the Uses clause:


function GetCDInfo(ID: Integer; vWord: Word):String;
      var msp : TMCI_INFO_PARMS;
          MediaString : array[0..255] of char;
          ret : longint;
      begin
       FillChar(MediaString, SizeOf(MediaString), #0);
       FillChar(msp, sizeof(msp), #0);
       msp.lpstrReturn := @MediaString;
       msp.dwRetSize := 255;
       ret := mciSendCommand(ID,
                             MCI_INFO,
                             vWord,
                             longint(@msp));
       if Ret <> 0 then begin
         MciGetErrorString(ret, @MediaString, SizeOf(MediaString));
         Result := StrPas(MediaString);
       end else Result := StrPas(MediaString);
      end;

      function GetSerialNumber(ID: Integer): string;
      begin
       Result := GetCDInfo(ID, MCI_INFO_MEDIA_IDENTITY);
      end;



procedure TForm1.Button1Click(Sender: TObject);
begin
 MediaPlayer1.DeviceType:= dtCDAudio;
 MediaPlayer1.Open;
 Label1.Caption:= GetSerialNumber(MediaPlayer1.DeviceID);
end;

Motaz
0
 
LVL 20

Expert Comment

by:Madshi
ID: 6261436
Hi lovedelphi,

wow, I just HAVE to help a guy with this name...   :-)

Please don't ask me why GetVolumeInformation returns different serial numbers under 9x and NT, I really don't know the reason. Motaz' suggestion (using MCI) is the correct solution. It gives you the same serial number in 9x and NT - well, in most cases at least. Recently I had a DVD ROM, which produced different MCI serial numbers, too. Sigh... But in most cases (at least for normal CDs) it works alright.

If you don't want to use the mediaPlayer, you can use my function, it needs less imports/uses:

function GetCDSerialNo(drive: char) : cardinal;
var mo    : TMCI_OPEN_PARMS;
    mp    : TMCI_INFO_PARMS;
    mg    : TMCI_GENERIC_PARMS;
    s1    : string;
    arrCh : array [0..255] of char;
begin
  result := 0;
  s1 := drive + ':';
  ZeroMemory(@mo, sizeOf(mo));
  ZeroMemory(@mp, sizeOf(mp));
  ZeroMemory(@mg, sizeOf(mg));
  mo.lpstrDeviceType  := pchar(MCI_DEVTYPE_CD_AUDIO);
  mo.lpstrElementName := pchar(s1);
  mp.lpstrReturn := arrCh;
  mp.dwRetSize   := sizeOf(arrCh) - 1;
  if mciSendCommand(0, MCI_OPEN,
                    MCI_OPEN_ELEMENT or MCI_OPEN_SHAREABLE or
                                        MCI_OPEN_TYPE or MCI_OPEN_TYPE_ID or MCI_WAIT,
                    cardinal(@mo)) = 0 then
    try
      if mciSendCommand(mo.wDeviceID, MCI_INFO, MCI_INFO_MEDIA_IDENTITY, cardinal(@mp)) = 0 then
        result := cardinal(StrToIntDef(arrCh, 0));
    finally mciSendCommand(mo.wDeviceID, MCI_CLOSE, 0, cardinal(@mg)) end;
end;

Regards, Madshi.
0
 

Author Comment

by:lovedelphi
ID: 6267727
thank you I got it!
0
 

Author Comment

by:lovedelphi
ID: 6267938
I can not give your score!!! how to...
0

Featured Post

On Demand Webinar - Networking for the Cloud Era

This webinar discusses:
-Common barriers companies experience when moving to the cloud
-How SD-WAN changes the way we look at networks
-Best practices customers should employ moving forward with cloud migration
-What happens behind the scenes of SteelConnect’s one-click button

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Objective: - This article will help user in how to convert their numeric value become words. How to use 1. You can copy this code in your Unit as function 2. than you can perform your function by type this code The Code   (CODE) The Im…
Introduction Raise your hands if you were as upset with FireMonkey as I was when I discovered that there was no TListview.  I use TListView in almost all of my applications I've written, and I was not going to compromise by resorting to TStringGrid…
With Secure Portal Encryption, the recipient is sent a link to their email address directing them to the email laundry delivery page. From there, the recipient will be required to enter a user name and password to enter the page. Once the recipient …
How to Install VMware Tools in Red Hat Enterprise Linux 6.4 (RHEL 6.4) Step-by-Step Tutorial

730 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question