一个由 Edit+Button 封装成的装件,在对象观察器中,看不到在组件中已被声明为published 的OnBtnClick方法.

Question

以下是源码,运行后点击按钮会出现message.但我希望组件在放在表单上后,在设计时期还可以为OnBtnClick写代码,请教封装组件的正确写法.谢谢!unit OPEN;interfaceuses
  SysUtils, Classes, Controls, StdCtrls, Messages,ExtCtrls,Dialogs;type
  TOPEN = class(TWinControl)
  private
    FDJNO:TEdit;
    FBtnOpen: TButton;
    { Private declarations }
  protected
    { Protected declarations }
  public
    constructor Create(AOwner:TComponent);override;
    destructor destroy;override;
    { Public declarations }
  published
    procedure OnBtnClick(Sender: TObject);
    { Published declarations }
  end;procedure Register;implementation//--------------------
procedure Register;
begin
  RegisterComponents('MyCls', [TOPEN]);
end;//--------------------
constructor TOPEN.Create(AOwner:TComponent);
begin
  inherited;
  Height:=40;
  width:=157;  FDJNO:=TEdit.Create(nil);
  FDJNO.parent:=self;
  FDJNO.top:=11;
  FDJNO.left:=50;
  FDJNO.width:=58;  FBtnOpen:=TButton.Create(nil);
  FBtnOpen.parent:=self;
  FBtnOpen.top:=11;
  FBtnOpen.left:=111;
  FBtnOpen.width:=32;
  FBtnOpen.caption:='开启';
  FBtnOpen.OnClick := OnBtnClick;
end;//---------
destructor TOPEN.destroy;
begin
  FDJNO.free;
  FBtnOpen.free;
  inherited;
end;//---------
procedure TOPEN.OnBtnClick(Sender: TObject);
begin
  showmessage('btn click');
end;end.

Answer 1

看看《delphi开发人员指南》，要把事件定义成属性！

Answer 2

private
   FOnBtnClick : TNotifyEvent;
published
 property OnBtnClick: TNotifyEvent read FOnBtnClick write FOnBtnClick;

Answer 3

TO tiankj:
按您讲的做了,下面是全部代码,但关于 TOPEN.FOnBtnClick 的代码无论怎样修改,都说
[Error] OPEN.pas(69): Declaration of 'FOnBtnClick' differs from previous declaration
//---------------------------------------
unit OPEN;interfaceuses
  SysUtils, Classes, Controls, StdCtrls, Messages,ExtCtrls,Dialogs;type
  TOPEN = class(TWinControl)
  private
    FDJNO:TEdit;
    FBtnOpen: TButton;
    FOnBtnClick : TNotifyEvent;
    { Private declarations }
  protected
    { Protected declarations }
  public
    constructor Create(AOwner:TComponent);override;
    destructor destroy;override;
    { Public declarations }
  published
//    procedure OnBtnClick(Sender: TObject);
    property OnBtnClick: TNotifyEvent read FOnBtnClick write FOnBtnClick;
    { Published declarations }
  end;procedure Register;implementation//--------------------
procedure Register;
begin
  RegisterComponents('MyCls', [TOPEN]);
end;//--------------------
constructor TOPEN.Create(AOwner:TComponent);
begin
  inherited;
  Height:=40;
  width:=157;  FDJNO:=TEdit.Create(nil);
  FDJNO.parent:=self;
  FDJNO.top:=11;
  FDJNO.left:=50;
  FDJNO.width:=58;  FBtnOpen:=TButton.Create(nil);
  FBtnOpen.parent:=self;
  FBtnOpen.top:=11;
  FBtnOpen.left:=111;
  FBtnOpen.width:=32;
  FBtnOpen.caption:='开启';
  FBtnOpen.OnClick := FOnBtnClick;
end;//----------
destructor TOPEN.destroy;
begin
  FDJNO.free;
  FBtnOpen.free;
  inherited;
end;procedure TOPEN.FOnBtnClick;
//procedure TOPEN.OnBtnClick(Sender: TObject);
//procedure TOPEN.OnBtnClick(Sender: TObject);TNotifyEvent;
begin
  showmessage('组件中按了btn ');
end;end.

Answer 4

public 
procedure OnBtnClick(Sender: TObject);
procedure TOPEN.OnBtnClick(Sender: TObject);
begin
  if assinged(FOnBtnClick) then
    OnBtnClick(self)
  showmessage('组件中按了btn ');
end;

Answer 5

TO  tiankj()  :这样会和 published 中的 OnBtnClick 同名,只好把 published 中的改名. 于是可以编译通过,但是点击btn时,没有任何反应.我的最终目的是:对于btn而言,既能把公用的代码写在组件里,又能在设计时期再添加代码. 
各位能否把一楼的代码复制到您的机器上试试呢?

Answer 6

constructor TOPEN.Create(AOwner:TComponent);
里
FBtnOpen.OnClick := OnBtnClick;该了吗？

Answer 7

调试好的unit OPEN;interfaceuses
  SysUtils, Classes, Controls, StdCtrls, Messages,ExtCtrls,Dialogs;type
  TOPEN = class(TWinControl)
  private
    FDJNO:TEdit;
    FBtnOpen: TButton;
    FOnBtnClick : TNotifyEvent;
    { Private declarations }
  protected
    { Protected declarations }
  public
    constructor Create(AOwner:TComponent);override;
    destructor destroy;override;
    { Public declarations }
  published
    procedure BtnClick(Sender: TObject);
    { Published declarations }
    property OnBtnClick: TNotifyEvent read FOnBtnClick write FOnBtnClick;  end;procedure Register;implementation//--------------------
procedure Register;
begin
  RegisterComponents('MyCls', [TOPEN]);
end;//--------------------
constructor TOPEN.Create(AOwner:TComponent);
begin
  inherited;
  Height:=40;
  width:=157;  FDJNO:=TEdit.Create(nil);
  FDJNO.parent:=self;
  FDJNO.top:=11;
  FDJNO.left:=50;
  FDJNO.width:=58;  FBtnOpen:=TButton.Create(nil);
  FBtnOpen.parent:=self;
  FBtnOpen.top:=11;
  FBtnOpen.left:=111;
  FBtnOpen.width:=32;
  FBtnOpen.caption:='开启';
  FBtnOpen.OnClick := BtnClick;
end;//---------
destructor TOPEN.destroy;
begin
  FDJNO.free;
  FBtnOpen.free;
  inherited;
end;//---------
procedure TOPEN.BtnClick(Sender: TObject);
begin
  showmessage('btn click');
  if assigned(FOnBtnClick) then
    OnBtnClick(self);
end;end.

Answer 8

对了对了,就是这个意思. BtnClick 用来写组件中通用的代码,OnBtnClick中写实例中添加的代码.
谢谢了,接分!