Элемент управления Edit, реагирующий на событие OnTimer

unit EditOnTime;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls,
  Forms, Dialogs, ExtCtrls, StdCtrls;

type
  TEditOnTime = class(TEdit)
  private
    FInterval: integer;
    FTimer: TTimer;
    FOnTimer: TNotifyEvent;
    procedure SetInterval(Interval: integer);
    procedure Timer(Sender: TObject);
  protected
    procedure KeyPress(var Key: char); override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  published
    property Interval: integer read FInterval write SetInterval default 750;
    property OnTimer: TNotifyEvent read FOnTimer write FOnTimer;
end;

procedure register;

implementation

//******************* RegisterComponent
// Здесь мы регистрируем компонент в IDE
procedure register;
begin
  RegisterComponents('MPS', [TEditOnTime]);
end;

//******************* TEditOnTime.SetInterval
// устанавливаем интервал таймера
procedure TEditOnTime.SetInterval(Interval: integer);
begin
  FInterval := Interval;
  if Assigned(FTimer) then
    FTimer.Interval := FInterval;
end;

//******************* TEditOnTime.Create
constructor TEditOnTime.Create(AOwner: TComponent);
begin
  FInterval := 750;
  inherited Create(AOwner);
  if not (csDesigning in ComponentState) then
    try
      FTimer := TTimer.Create(self);
      FTimer.Enabled := false;
      FTimer.Interval := FInterval;
      FTimer.OnTimer := Timer;
    except
      FreeAndNil(FTimer);
    end;
end;

//******************* TEditOnTime.Destroy
destructor TEditOnTime.Destroy;
begin
  if Assigned(FTimer) then
    FreeAndNil(FTimer);
  inherited Destroy;
end;

//******************* TEditOnTime.OnTimer
procedure TEditOnTime.Timer(Sender: TObject);
begin
  FTimer.Enabled := false;
  if Assigned(FOnTimer) then
    FOnTimer(self);
end;

//******************* TEditOnTime.KeyPress
procedure TEditOnTime.KeyPress(var Key: char);
begin
  FTimer.Enabled := false;
  inherited KeyPress(Key);
  FTimer.Enabled := (Text <> '') and Assigned(FTimer)
    and Assigned(FOnTimer);
end;

end.