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Note: need to read more about using TThread.Synchronize or TThread.Queue

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    mmo1: TMemo;
    tmr1: TTimer;
    procedure Button1Click(Sender: TObject);
    procedure tmr1Timer(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

  TMyThread = class(TThread)
    protected
    procedure Execute; override;
 end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


procedure TMyThread.Execute;
begin
   form1.mmo1.Lines.add('start threaded timer after wake: '+formatdatetime('hh:mm:ss',now()));
   sleep(5000);
   form1.mmo1.Lines.add('end threaded timer after wake: '+formatdatetime('hh:mm:ss',now()));
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  TMyThread.Create(False);
end;

procedure TForm1.tmr1Timer(Sender: TObject);
begin
   mmo1.Lines.add('regular timer: '+formatdatetime('hh:mm:ss',now()));
end;

end.

To stop a thread that is processing a never-ending loop, you can use a flag to signal the thread to exit. Here’s how you can modify the example to include a mechanism for stopping the thread:

Define a flag in the thread class:

  type TMyThread = class(TThread)
     private
        FStop: Boolean;
     protected
        procedure Execute; override;
     public
        procedure Stop;
  end;

Implement the Execute method to check the flag:

procedure TMyThread.Execute;
begin
  while not Terminated and not FStop do begin
    // codes here //
  end;
end;

Implement the Stop method to set the flag:

procedure TMyThread.Stop;
begin
  FStop := True;
end;

Create and stop the thread from the main form:

var
  MyThread: TMyThread;

procedure TForm1.Button1Click(Sender: TObject);
begin
  MyThread := TMyThread.Create(False);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  if Assigned(MyThread) then
  begin
    MyThread.Stop;
    MyThread.WaitFor;
    FreeAndNil(MyThread);
  end;
end;

In this example:

The FStop flag is used to signal the thread to stop. The Execute method checks the FStop flag in each iteration of the loop. The Stop method sets the FStop flag to True. The main form creates the thread with Button1Click and stops it with Button2Click. This approach ensures that the thread can exit gracefully when the Stop method is called.

Another Solution using Timer Event to do some background task:

unit BackgroundThread;
interface
uses Classes, SysUtils;
type
  TBackgroundProcessThread = class(TThread)
  protected
    procedure Execute; override;
  end;

implementation

procedure TBackgroundProcessThread.Execute;
begin
  while not Terminated do begin
    // Place your CPU-intensive process here
    Sleep(10000); // Simulate a 10-second interval
  end;
end;

end.

uses BackgroundThread;

procedure TForm1.Timer1Timer(Sender: TObject);
var
  BackgroundThread: TBackgroundProcessThread;
begin
  BackgroundThread := TBackgroundProcessThread.Create(True);
  BackgroundThread.FreeOnTerminate := True;
  BackgroundThread.Start;
end;