如何向非可视控件发送自定义消息？非可视控件中如何响应自定义消息？ (300分)

各位老师，向您讨教：
1、如何向非可视控件发送自定义消息？
2、非可视控件中如何响应自定义消息？
3、有没有办法向一组自定义的非可视化控件广播自定义的消息？
这些控件继承Tcomponent

请看:
http://www.delphibbs.com/delphibbs/dispq.asp?lid=094911
http://www.delphibbs.com/delphibbs/dispq.asp?lid=195602
http://www.delphibbs.com/delphibbs/dispq.asp?lid=458041

应该够用了.

楼上的兄台：谢谢！
这些控件继承Tcomponent没有句柄，怎么向他们发送消息呀？？？

使用 FWindowHandle := AllocateHWnd(WndProc);获得一个句柄。

下面是我写的一个监视剪贴板变动的非可视控件，还没测试过，不知道对不对：
unit ZeroClipBoardSpy;
{
Web Site:http://myzeroworld.yeah.net
}


interface

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

type
TZeroClipBoardSpy = class(TComponent)
private
FWindowHandle:THandle;

//next clipboard viewer handle
FNextViewerHandle:THandle;
fOnChange: TNotifyEvent;

fStarted:boolean;


//main procedure
procedure WndProc(var Msg: TMessage);
{ Private declarations }
protected
{ Protected declarations }
public
constructor Create(AOwner: TComponent);override;
destructor Destroy; override;

procedure StartSpy;
procedure StopSpy;
{ Public declarations }
published
property OnChange:TNotifyEvent read fOnChange write fOnChange;
{ Published declarations }
end;

procedure Register;

implementation

procedure Register;
begin
RegisterComponents('Zero Component', [TZeroClipBoardSpy]);
end;

{ TZeroClipBoardSpy }

constructor TZeroClipBoardSpy.Create(AOwner: TComponent);
begin
inherited;

FWindowHandle := AllocateHWnd(WndProc);

FNextViewerHandle:=0;

fStarted:=false;
end;

destructor TZeroClipBoardSpy.Destroy;
begin
inherited;

//call stop spy on destory
StopSpy;

//release handle
DeallocateHWnd(FWindowHandle);
end;

procedure TZeroClipBoardSpy.StartSpy;
begin
if not(fStarted) then
begin
fNextViewerHandle := SetClipboardViewer(fWindowHandle);
fStarted:=true;
end;
end;

procedure TZeroClipBoardSpy.StopSpy;
begin
if fStarted then
begin
ChangeClipboardChain(fWindowHandle, fNextViewerHandle);
fStarted:=false;
end;
end;

procedure TZeroClipBoardSpy.WndProc(var Msg: TMessage);
begin
case Msg.Msg of
WM_DRAWCLIPBOARD: //clipboard change
try
try
if assigned(fOnChange) then
fOnChange(Self);
finally
msg.Result := SendMessage(WM_DRAWCLIPBOARD, FNextViewerHandle, 0, 0);
end;
except
Application.HandleException(Self);
end;
WM_CHANGECBCHAIN://process change chain message
try
if THandle(msg.wParam) = FNextViewerHandle then
begin
FNextViewerHandle := msg.lParam;
msg.Result := 0;
end
else
msg.Result := SendMessage(FNextViewerHandle, WM_CHANGECBCHAIN,msg.wParam, msg.lParam);
except
Application.HandleException(Self);
end;

else
with Msg do
Result := DefWindowProc(FWindowHandle, Msg, wParam, lParam);

end;{Case}
end;

end.

看一下Timer的源码你就全明白了
要先分配给他一个句柄..........

多人接受答案了。