进程间传递消息（发送和接收系统消息）

{
2002.07.22
关于如何发送和接收系统消息
作者：王珍义
nickname:LargeWang(老王)
QQ: 33728007
欢迎光临鹏业软件 www.pengesoft.com.cn

以下代码Delphi7.0通过，编译后启动两个进程，然后在一个窗口中点击Button1试试。
}

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Button1: TButton;
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
private
Msg: LongInt;
{ Private declarations }
protected
procedure WndProc(var Message: TMessage); override;
public

{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
Msg := RegisterWindowMessage('wm_mymessage');
Self.BringToFront;
end;

procedure TForm1.WndProc(var Message: TMessage);
begin
if Message.Msg = Msg then begin
Caption := '';
ShowMessage('收到消息了');
end
else begin
inherited;
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
M: TMessage;
B: DWord;
begin
M.Msg := Msg;
B := BSM_ALLCOMPONENTS;
BroadcastSystemMessage(BSF_POSTMESSAGE, @B , M.Msg, M.WParam, M.LParam );
end;

end.

////窗口文件
object Form1: TForm1
Left = 192
Top = 107
Width = 696
Height = 480
Caption = 'Form1'
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
OldCreateOrder = False
OnCreate = FormCreate
PixelsPerInch = 96
TextHeight = 13
object Button1: TButton
Left = 204
Top = 84
Width = 75
Height = 25
Caption = 'Button1'
TabOrder = 0
OnClick = Button1Click
end
end