Using VCL TTimer in Delphi console application

Question

As the question subject says. I have a console application in Delphi, which contains a TTimer variable. The thing I want to do is assign an event handler to T

Answer 1

Your code does not work because TTimer component internally uses WM_TIMER message processing and a console app does not have a message loop. To make your code work you should create a message pumping loop yourself:

program TimerTest;

{$APPTYPE CONSOLE}

uses
  SysUtils, Windows,
  extctrls;

type
  TEventHandlers = class
    procedure OnTimerTick(Sender : TObject);
  end;

var
  Timer : TTimer;
  EventHandlers : TEventHandlers;


procedure TEventHandlers.OnTimerTick(Sender : TObject);
begin
  writeln('Hello from TimerTick event');
end;

procedure MsgPump;
var
  Unicode: Boolean;
  Msg: TMsg;

begin
  while GetMessage(Msg, 0, 0, 0) do begin
    Unicode := (Msg.hwnd = 0) or IsWindowUnicode(Msg.hwnd);
    TranslateMessage(Msg);
    if Unicode then
      DispatchMessageW(Msg)
    else
      DispatchMessageA(Msg);
  end;
end;

begin
  EventHandlers := TEventHandlers.Create();
  Timer := TTimer.Create(nil);
  Timer.Enabled := false;
  Timer.Interval := 1000;
  Timer.OnTimer := EventHandlers.OnTimerTick;
  Timer.Enabled := true;
  MsgPump;
end.