用SendNotifyMessage代替PostMessage避免消息丢失（WIN7下消息队列的默认长度是10000，队列满后消息将被丢弃）

 1 unit Unit1; 
 2 
 3 interface 
 4 
 5 uses 
 6   Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
 7   Dialogs, StdCtrls; 
 8 
 9 const 
10   UM_ADD = WM_USER + 100; 
11 
12 type 
13   TForm1 = class(TForm) 
14     Label1: TLabel; 
15     procedure FormCreate(Sender: TObject); 
16   private 
17     FVal: Integer; 
18     procedure OnMsgAdd(var Msg: TMsg); message UM_ADD; 
19   public 
20     { Public declarations } 
21   end; 
22 
23 var 
24   Form1: TForm1; 
25 
26 implementation 
27 
28 {$R *.dfm} 
29 
30 procedure TForm1.FormCreate(Sender: TObject); 
31 var 
32   i: Integer; 
33 begin 
34   for i:=0 to 1000000 do 
35     PostMessage(Handle, UM_ADD, 0, 0); 
36 end; 
37 
38 procedure TForm1.OnMsgAdd(var Msg: TMsg); 
39 begin 
40   Inc(FVal); 
41   Label1.Caption := IntToStr(FVal); 
42 end; 
43 
44 end.