Timing and VCL synchronize (in/from thread)

Question

I would like to refresh a Treenode.text (with the elapsed time) and use a timer from the same thread. As i read its not recommend to use TTimer* in a thread, but then, what to use instead? Thank You.

*I want to use some timing instead of sleep(). Not just because thats cheesy(?), but i have to, because otherwise i can refresh treenodetext only in every sec.) >>

unit master_slave

...

Tsrch_slave_thread = class(TThread)   
protected
  procedure Execute; override;
public
  master: TMaster;         
end;

TMaster = class(TObject)
private
  ...
  FMasterNode: TTreeview; 
  Fsw: TStopWatch;
  Fslave_search_thread : Tsrch_slave_thread;
  ...
end;

...

implementation

...

procedure Tsrch_slave_thread.Execute;
var
  searchactive: integer;
begin
  while not terminated do begin
    searchactive := master.CMD_LISTCNT 
    if searchactive = 1 then //(master.CMD_LISTCNT's return value = 1, if master finished search on the bus)
      exit;
    sleep(1000); //dont want to flood the master with UDP packets... (master.CMD_LISTCNT sends UDP packets)
    synchronize(procedure begin
      with FmasterNode do  
        text := text + floattostr(Fsw.ElapsedMilliseconds / 1000);
    end);
  end;
end;

Answer 1

Instead of Sleep(1000), use a waitable event.

For example TSimpleEvent.

FMySimpleEvent.WaitFor(1000);

If you want to exit the thread early, override the TThread.DoTerminate method and call:

FMySimpleEvent.SetEvent;

Something like this:

procedure Tsrch_slave_thread.Execute;
var
  searchactive: integer;
begin
  while not terminated do begin
    searchactive := master.CMD_LISTCNT 
    if searchactive = 1 then (master.CMD_LISTCNT's return value = 1, if search finished)
      exit;
    if (FMySimpleEvent.WaitFor(1000) = wrTimeOut) then
      synchronize(procedure begin
        with FmasterNode do  
          text := text + floattostr(Fsw.ElapsedMilliseconds / 1000);
      end);
  end;
end;

procedure Tsrch_slave_thread.DoTerminate;
begin
  Inherited;
  FMySimpleEvent.SetEvent;
end;