Title: How to get the primary domain controller (PDC)
type
EAccessDenied = Exception;
EInvalidOwner = Exception;
EInsufficientBuffer = Exception;
ELibraryNotFound = Exception;
NET_API_STATUS = Integer;
const
NERR_Success = 0;
var
NTNetGetDCName: function (Server, Domain: pWideChar; var DC: pWideChar): NET_API_STATUS; stdcall;
NTNetGetDCNameA: function (Server, Domain: PChar; var DC: PChar): NET_API_STATUS; stdcall;
NTNetApiBufferFree: function (lpBuffer: Pointer): NET_API_STATUS; stdcall;
procedure NetCheck(ErrCode: NET_API_STATUS);
begin
if ErrCode NERR_Success then
begin
case ErrCode of
ERROR_ACCESS_DENIED:
raise EAccessDenied.Create('Access is Denied');
ERROR_INVALID_OWNER:
raise EInvalidOwner.Create('Cannot assign the owner of this object.');
ERROR_INSUFFICIENT_BUFFER:
raise EInsufficientBuffer.Create('Buffer passed was too small');
else
raise Exception.Create('Error Code: ' + IntToStr(ErrCode) + #13 +
SysErrorMessage(ErrCode));
end;
end;
end;
function GetPDC(szSystem: string): string;
{ if szSystem = '' return the PDC else return DC for that domain }
const
NTlib = 'NETAPI32.DLL';
Win95lib = 'RADMIN32.DLL';
var
pAnsiDomain: PChar;
pDomain: PWideChar;
System: array[1..80] of WideChar;
ErrMode: Word;
LibHandle: THandle;
begin
Result := '';
LibHandle := 0;
try
if Win32Platform = VER_PLATFORM_WIN32_NT then
begin
ErrMode := SetErrorMode(SEM_NOOPENFILEERRORBOX);
LibHandle := LoadLibrary(NTlib);
SetErrorMode(ErrMode);
if LibHandle = 0 then
raise ELibraryNotFound.Create('Unable to map library: ' +
NTlib); @NTNetGetDCName := GetProcAddress(Libhandle, 'NetGetDCName');
@NTNetApiBufferFree := GetProcAddress(Libhandle,
'NetApiBufferFree');
try
if szSystem '' then
NetCheck(NTNetGetDCName(nil, StringToWideChar(szSystem, @System, 80), pDomain))
else
NetCheck(NTNetGetDCName(nil, nil, pDomain));
Result := WideCharToString(pDomain);
finally
NetCheck(NTNetApiBufferFree(pDomain));
end;
end
else
begin
ErrMode := SetErrorMode(SEM_NOOPENFILEERRORBOX);
LibHandle := LoadLibrary(Win95lib);
SetErrorMode(ErrMode);
if LibHandle = 0 then
raise ELibraryNotFound.Create('Unable to map library: ' +
Win95lib); @NTNetGetDCNameA := GetProcAddress(Libhandle, 'NetGetDCNameA');
@NTNetApiBufferFree := GetProcAddress(LibHandle, 'NetApiBufferFree');
try
if szSystem '' then
NetCheck(NTNetGetDCNameA(nil, PChar(szSystem), pAnsiDomain))
else
NetCheck(NTNetGetDCNameA(nil, nil, pAnsiDomain));
Result := StrPas(pAnsiDomain);
finally
NetCheck(NTNetApiBufferFree(pAnsiDomain));
end;
end;
finally
if LibHandle 0 then
begin
FreeLibrary(Libhandle); // free handle if it has been allocated
end;
end;
end;
Usage Examples:
procedure TForm1.Button1Click(Sender: TObject);
begin
try
Screen.Cursor := crHourGlass;
label1.Caption := GetPDC('');
finally
Screen.Cursor := crDefault;
end;
end;