Как получить событие о смене реестра?

function RegNotifyChangeKeyValue(hKey: HKEY; bWatchSubtree: Boolean;
    dwNotifyFilter: DWORD; hEvent: THandle; fAsynchronus: Boolean): Longint; stdcall;
    external 'advapi32.dll' name 'RegNotifyChangeKeyValue';

 
procedure TForm1.Button1Click(Sender: TObject);
const
  dwFilter = REG_NOTIFY_CHANGE_NAME or
             REG_NOTIFY_CHANGE_ATTRIBUTES or
             REG_NOTIFY_CHANGE_LAST_SET or
             REG_NOTIFY_CHANGE_SECURITY;
var
  hMainKey, hSubKey: HKEY;
  hNotifyEvent: THandle;
  ErrorCode: Longint;
begin
  hMainKey := HKEY_CURRENT_USER;
  ErrorCode := RegOpenKeyEx(hMainKey,
    'Software\Microsoft\Windows\CurrentVersion\Run', 0, KEY_ALL_ACCESS, hSubKey);
  if ErrorCode = ERROR_SUCCESS then
  try
    hNotifyEvent := CreateEvent(nil, True, False, nil);
    if hNotifyEvent <> 0 then
    try
      ErrorCode := RegNotifyChangeKeyValue(hSubKey, True, dwFilter, hNotifyEvent, True);
      if ErrorCode = ERROR_SUCCESS then
        case WaitForSingleObject(hNotifyEvent, INFINITE) of
          WAIT_FAILED: ShowMessage(SysErrorMessage(GetLastError));
          WAIT_OBJECT_0: ShowMessage('Произошли изменения в реестре.');
        end;
    finally
      CloseHandle(hNotifyEvent);
    end
    else
      ShowMessage(SysErrorMessage(GetLastError));
  finally
    RegCloseKey(hSubKey);
  end;
  if ErrorCode <> ERROR_SUCCESS then
    ShowMessage(SysErrorMessage(ErrorCode));
end;

Автор: Александр (Rouse_) Багель

{
  An application can be notified of changes in the data stored in the
  Windows clipboard by registering itself as a Clipboard Viewer.
 
  Clipboard viewers use two API calls and several messages to communicate
  with the Clipboard viewer chain. SetClipboardViewer adds a window to the
  beginning of the chain and returns a handle to the next viewer in the chain.
  ChangeClipboardChain removes a window from the chain. When a clipboard change occurs,
  the first window in the clipboard viewer chain is notified via the WM_DrawClipboard
  message and must pass the message on to the next window. To do this, our application
  must store the next window along in the chain to forward messages to and also respond
  to the WM_ChangeCBChain message which is sent whenever any other clipboard viewer on
  the system is added or removed to ensure the next window along is valid.
}
 
 
unit Unit1;
 
interface
 
uses
  Windows, Messages, Forms, Classes, Controls, StdCtrls;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender : TObject);
    procedure Button2Click(Sender : TObject);
    procedure FormCreate(Sender : TObject);
    procedure FormDestroy(Sender : TObject);
  private
    FNextClipboardViewer: HWND;
    procedure WMChangeCBChain(var Msg : TWMChangeCBChain); message WM_CHANGECBCHAIN;
    procedure WMDrawClipboard(var Msg : TWMDrawClipboard); message WM_DRAWCLIPBOARD;
  end;
 
var
  Form1 : TForm1;
 
implementation
 
{$R *.DFM}
 
procedure TForm1.FormCreate(Sender : TObject);
begin
  { Initialize variable }
  FNextClipboardViewer := 0;
end;
 
 
procedure TForm1.Button1Click(Sender : TObject);
begin
  if FNextClipboardViewer <> 0 then
    MessageBox(0, 'This window is already registered!', nil, 0)
  else
    { Add to clipboard chain }
    FNextClipboardViewer := SetClipboardViewer(Handle);
end;
 
 
procedure TForm1.Button2Click(Sender : TObject);
begin
  { Remove from clipboard chain }
  ChangeClipboardChain(Handle, FNextClipboardViewer);
  FNextClipboardViewer := 0;
end;
 
 
procedure TForm1.WMChangeCBChain(var Msg : TWMChangeCBChain);
begin
  inherited;
  { mark message as done }
  Msg.Result := 0;
  { the chain has changed }
  if Msg.Remove = FNextClipboardViewer then
    { The next window in the clipboard viewer chain had been removed. We recreate it. }
    FNextClipboardViewer := Msg.Next
  else
    { Inform the next window in the clipboard viewer chain }
    SendMessage(FNextClipboardViewer, WM_CHANGECBCHAIN, Msg.Remove, Msg.Next);
end;
 
 
procedure TForm1.WMDrawClipboard(var Msg : TWMDrawClipboard);
begin
  inherited;
  { Clipboard content has changed }
  try
    MessageBox(0, 'Clipboard content has changed!', 'Clipboard Viewer', MB_ICONINFORMATION);
  finally
    { Inform the next window in the clipboard viewer chain }
    SendMessage(FNextClipboardViewer, WM_DRAWCLIPBOARD, 0, 0);
  end;
end;
 
 
procedure TForm1.FormDestroy(Sender : TObject);
begin
  if FNextClipboardViewer <> 0 then
  begin
    { Remove from clipboard chain }
    ChangeClipboardChain(Handle, FNextClipboardViewer);
    FNextClipboardViewer := 0;
  end;
end;
 
end.

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