Problems reading registry from Delphi 7 on Windows 7 64 bit

Question

I think this question was already asked, but I couldn't find a solution which works for me. I use Delphi 7 under Windows 7 Ultimate, 64 bit. Actually I started writing application under 32 bit OS, but then changes PC, so now its 64. In my program I use registration process with Licence ID generated from PROGID value of Windows. Unfortunately it doesn't read the value, seems like it is looking in a different folder, probably redirected by Windows 64 to 32 bit registry. Can you help? This is the code I use:

 Registry := TRegistry.Create(KEY_READ OR $0100);
    try
      Registry.Lazywrite := false;
      Registry.RootKey := HKEY_LOCAL_MACHINE;
      if CheckForWinNT = true then
       Begin
       if not Registry.OpenKeyReadOnly('\Software\Microsoft\Windows NT\CurrentVersion') then showmessagE('cant open');
       end
      else
        Registry.OpenKeyReadOnly('\Software\Microsoft\Windows\CurrentVersion');
      result := Registry.ReadString('ProductID'); 
      Registry.CloseKey;
    finally
      Registry.Free;
    end; // try..finally

Also, do you know how to find whether program is running under 64 bit or 32 bit computer in Delphi 7?

Answer 1

Here is some Delphi 7 code to detect whether you are running in a 64-bit OS:

function Is64BitOS: Boolean;
type
  TIsWow64Process = function(Handle:THandle; var IsWow64 : BOOL) : BOOL; stdcall;
var
  hKernel32 : Integer;
  IsWow64Process : TIsWow64Process;
  IsWow64 : BOOL;
begin
  // we can check if the operating system is 64-bit by checking whether
  // we are running under Wow64 (we are 32-bit code). We must check if this
  // function is implemented before we call it, because some older versions
  // of kernel32.dll (eg. Windows 2000) don't know about it.
  // see http://msdn.microsoft.com/en-us/library/ms684139%28VS.85%29.aspx
  Result := False;
  hKernel32 := LoadLibrary('kernel32.dll');
  if (hKernel32 = 0) then RaiseLastOSError;
  @IsWow64Process := GetProcAddress(hkernel32, 'IsWow64Process');
  if Assigned(IsWow64Process) then begin
    IsWow64 := False;
    if (IsWow64Process(GetCurrentProcess, IsWow64)) then begin
      Result := IsWow64;
    end
    else RaiseLastOSError;
  end;
  FreeLibrary(hKernel32);
end;

(Shamelessly plagiarized from myself, here)

It looks like you are passing KEY_WOW64_64KEY ($0100), so you should be looking at the 64-bit registry branch. If you want to look at the 32-bit registry branch, you should pass KEY_WOW64_32KEY ($0200).

Answer 2

You already asked this question see http://stackoverflow.com/questions/2666807/registry-readstring-method-is-not-working-in-windows-7-in-delphi-7.

So you know that you have to add $0100 in the TRegistry.Create. The problem with your code is that you use OpenKeyReadOnly which resets the Access property of the registry to KEY_READ, so KEY_READ or $0100 is lost.

Just use OpenKey instead of OpenKeyReadOnly, this won't reset your Access property.

Answer 3

As to your side question, whether it's a 64-bit computer (which is not the same thing as running on a 64-bit OS), have a look at the answers to this question.