[ecfisa]

Hola joseprad.

Un ejemplo en el que activas/desactivas los eventos por medio de dos botones:

Código Delphi [-]
...
type
  TForm1 = class(TForm)
    ...
    DBGrid1: TDBGrid;
    btnDeactivate: TButton;
    btnActivate: TButton;
    procedure FormCreate(Sender: TObject);
    procedure btnDeactivateClick(Sender: TObject);
    procedure btnActivateClick(Sender: TObject);
    procedure DataSetBeforePost(DataSet: TDataSet);
    procedure DataSetAfterPost(DataSet: TDataSet);
  private
     FOldBeforePost,
     FOldAfterPost: TDataSetNotifyEvent;
  ...

  end;
...

implementation

procedure TForm1.FormCreate(Sender: TObject);
begin
  with DBGrid1.DataSource.DataSet do
  begin
    FOldBeforePost:= BeforePost;
    FOldAfterPost := AfterPost;
  end;
end;

procedure TForm1.btnDeactivateClick(Sender: TObject);
begin
  with DBGrid1.DataSource.DataSet do
  begin
    BeforePost:= nil;
    AfterPost := nil;
  end;
end;

procedure TForm1.btnActivateClick(Sender: TObject);
begin
  with DBGrid1.DataSource.DataSet do
  begin
    BeforePost:= FOldBeforePost;
    AfterPost := FOldAfterPost;
  end;
end;

procedure TForm1.DataSetAfterPost(DataSet: TDataSet);
begin
  ShowMessage('Evento AfterPost');
end;

procedure TForm1.DataSetBeforePost(DataSet: TDataSet);
begin
  ShowMessage('Evento BeforePost')
end;
...

Saludos