Delphi 使用自定义消息

1、先用Const 定义一个常量，例如 const WM_MyMessage=WM_USER+$200;
2、在要实现的unit中定义一个私有方法
   procedure doMyMessage(var msg:TMessage);message WM_MyMessage;
3、实现这个私有方法
    procedure TForm1.doMyMessage(var msg:TMessage);
begin
  //
  if msg.Msg= WM_MyMessage then
    showmessage('好啊')
  else
    showmessage('不好');
 
end;
 
 
4、最重要 把这个消息广播出去 Form1.Perform(WM_MyMessage,0,0);
 
下面是实现的代码
 
 
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
const WM_MyMessage=WM_USER+$200;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    procedure doMyMessage(var msg:TMessage);message WM_MyMessage;
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
procedure TForm1.doMyMessage(var msg:TMessage);
begin
  //
  if msg.Msg= WM_MyMessage then
    showmessage('好啊')
  else
    showmessage('不好');
 
end;
 
procedure TForm1.Button1Click(Sender: TObject);
 
begin
   Form1.Perform(WM_MyMessage,0,0);
 
end;
 
end.