how to handle postmessage in TThread Objects

Try PostThreadMessage

Bill

If I understood right, you want to start your thread when you receive a PostMessage?

Doing something like this when you receive the PostMessage should start it:
MyThread := TMyThread.Create(False);

If that is already what you did or I didn't understood correctly your question, don't hesitate to tell me!
GunDamn

ok,
thread this in execution and within this execution desire to execute postmessage, thread executes the instruction but not the procedure assigned to the same one (to postmessage). The same it happens to me with postthreadmessage.

Ruben  
 

Are you posting your message with the right window handle?
I suppose you wish to post a message outSide of the Thread?
If not, maybe you could try to put your PostMessage procedure outside your thread.

If it still doesn't work, I will need a code sample to help you further.
GunDamn

it may do in the following way :

   TRunThread =class(TThread)
   protected
   private
     FWindowHandle: HWND;
     procedure WndProc(var Msg: TMessage);
     procedure DoAnything;
   public
     procedure Execute;override;
   end;
 
procedure TRunThread.Execute;
begin
  FWindowHandle := AllocateHWnd(WndProc);
  DoSomething;
  DeallocateHWnd(FWindowHandle);
end;


procedure TRunThread.DoAnything;
begin
 ...
end;

procedure TRunThread.WndProc(var Msg: TMessage);
begin
  with Msg do
    if Msg = WM_Thread then
      try
        DoAnything;
      except
        Application.HandleException(Self);
      end
    else
      Result := DefWindowProc(FWindowHandle, Msg, wParam, lParam);
end;

 

in execute  add next text:

  while GetMessage(Msg,0, 0, 0) do
  begin
    TranslateMessage(Msg);
    DispatchMessage(Msg);
  end;



and remove procedure DoSomething;

in execute  add next text:

  while GetMessage(Msg,0, 0, 0) do
  begin
    TranslateMessage(Msg);
    DispatchMessage(Msg);
  end;



and remove procedure DoSomething;

why not postmessage not processing wmcontrolclose???????

unit pruebas;

interface

uses
  Messages, Forms, Classes, SysUtils,Windows, Dialogs;

const
  wm_Controlclose = WM_User + 1;

type
  ThSwt_Input = class(TThread)
 
  public

    constructor Create(CreateSuspended: Boolean);
    procedure   WmControlclose(var Msg: TMessage); Message wm_ControlClose;

             
  private
    { Private declarations }
    //
  protected
    procedure Execute; override;
    procedure ProceseMessage;
                                 
  end;

var
  ThSwitch_In     : ThSwt_Input;

implementation

{ Important: Methods and properties of objects in VCL can only be used in a
  method called using Synchronize, for example,

      Synchronize(UpdateCaption);

  and UpdateCaption could look like,

    procedure THDataQueueInput.UpdateCaption;
    begin
      Form1.Caption := 'Updated in a thread';
    end; }

{ THDataQueueInput }

constructor ThSwt_Input.Create(CreateSuspended: Boolean);
begin
   Inherited Create(CreateSuspended);
end;

procedure ThSwt_Input.Execute;
begin

  { Place thread code here }
ProceseMessage;
   
end;

procedure ThSwt_Input.ProceseMessage;
var
s1 : string;
begin

  PostMessage(Handle,wm_Controlclose ,0,0);

  s1 := 'continuo con la ejecucion del programa';
  showmessage(s1);
 
  // mas codigo del programa

end;

procedure ThSwt_Input.WmControlclose(var Msg: TMessage);
var
s1 : string;
begin
  // realiza proceso interno
  s1 := 'ejecuta postmessage';
  showmessage(s1);
end;                          

end.

why postmessage not processing wmcontrolclose???????

unit pruebas;

interface

uses
  Messages, Forms, Classes, SysUtils,Windows, Dialogs;

const
  wm_Controlclose = WM_User + 1;

type
  ThSwt_Input = class(TThread)
 
  public

    constructor Create(CreateSuspended: Boolean);
    procedure   WmControlclose(var Msg: TMessage); Message wm_ControlClose;

             
  private
    { Private declarations }
    //
  protected
    procedure Execute; override;
    procedure ProceseMessage;
                                 
  end;

var
  ThSwitch_In     : ThSwt_Input;

implementation

{ Important: Methods and properties of objects in VCL can only be used in a
  method called using Synchronize, for example,

      Synchronize(UpdateCaption);

  and UpdateCaption could look like,

    procedure THDataQueueInput.UpdateCaption;
    begin
      Form1.Caption := 'Updated in a thread';
    end; }

{ THDataQueueInput }

constructor ThSwt_Input.Create(CreateSuspended: Boolean);
begin
   Inherited Create(CreateSuspended);
end;

procedure ThSwt_Input.Execute;
begin

  { Place thread code here }
ProceseMessage;
   
end;

procedure ThSwt_Input.ProceseMessage;
var
s1 : string;
begin

  PostMessage(Handle,wm_Controlclose ,0,0);

  s1 := 'continuo con la ejecucion del programa';
  showmessage(s1);
 
  // mas codigo del programa

end;

procedure ThSwt_Input.WmControlclose(var Msg: TMessage);
var
s1 : string;
begin
  // realiza proceso interno
  s1 := 'ejecuta postmessage';
  showmessage(s1);
end;                          

end.

you must create Window in Thread and MessageQueue

  like in my text

FWindowHandle := AllocateHWnd(WndProc);



 

 

procedure ThSwt_Input.Execute;
begin
  FWindowHandle := AllocateHWnd(WndProc);
  while GetMessage(Msg,0, 0, 0) do
  begin
    TranslateMessage(Msg);
    DispatchMessage(Msg);
  end;
  DeallocateHWnd(FWindowHandle);
end;



you may postmessage  out From Thread

var
  Thread:ThSwt_Input;

 
procedure TForm1.Button1Click(Sender: TObject);
begin
  Thread := ThSwt_Input.Create(True);
  IsTread:=True;
  Thread.OnTerminate := ThreadTerminate;
  Thread.FreeOnTerminate := True;
  Thread.Resume;
end;


procedure TForm1.Button2Click(Sender: TObject);
begin
  SendMessage(Thread.FWindowHandle, WM_USER + 1, 0, 0);
end;




procedure ThSwt_Input.ProceseMessage;
begin
 Synchronize(DoAnything);
end;




procedure ThSwt_Input.DoAnything;
var
s1 : string;
begin
 s1 := 'ejecuta postmessage';
 showmessage(s1);
end;

Not wishing to muddy the waters, but you might also look
at the api PostThreadMessage,

Iuse it for talking to threads, you dont need a window handle.

as

oops sorry Bill, you said that.
Any way I do the following..

procedure TMyThread.Execute;
var
   Msg : TMsg;
begin
  PeekMessage(msg, 0, WM_USER, WM_USER, PM_NOREMOVE);// start the thread message queue
  MyThreadId:=ThreadID;// stick the thread id somewhere I can find it.
  MyStartup;
  while True do begin
      if Terminated then Break;//check if anyone called mythread.terminate-
      IF NOT GetMessage(Msg, 0, 0, 0) THEN Break;//could peak here to prevent stall, this returns false if WM_Quit is posted
      MyProcessMsg(msg);//I process the message
      end;
  MyCleanup;
end;

In the main program I call
PostThreadMessage(MyThreadId,wm_xxx,0,0);

agree
its work :)


rbarzallo wants
postmessage  inner Thread
 
 

Dear SMakarenko


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Thanks !

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Community Support Moderator
Experts Exchange

No comment has been added lately, so it's time to clean up this TA.
I will leave a recommendation in the Cleanup topic area that this question is:

Accept SMakarenko's comment as answer
(will be submitted on 06/18/2003 to cleanup)

Please leave any comments here within the next seven days.
 
PLEASE DO NOT ACCEPT THIS COMMENT AS AN ANSWER!
 
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