delphi - Delphi XE4 中动态创建的 TPopup 菜单不会调用其项目的 OnClick 事件处理程序

Question

我想测试一些东西并创建了一个简单的动态弹出菜单示例。我不得不意识到弹出菜单正常显示，但它不调用 onClick 事件处理程序。我试图重命名所有内容以避免名称冲突，将事件处理程序设为虚拟、公开，但并没有解决问题。我已经重新启动了 IDE（我认为这段代码应该可以正常工作）但它是一样的。编译器选项是新的项目默认值。静态创建的（放置在表单上）弹出菜单工作正常，只是动态创建的需要休息一下。我应该用一些值填充动态菜单的哪个属性？求大神解释一下原因！

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.Menus;

type
  TForm1 = class(TForm)
    Button1: TButton;
    staticPopupMenu: TPopupMenu;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
    procedure addMenuItem( popupmenu_ : TPopupMenu; caption_ : string; tag_ : integer; onClick_ : TNotifyEvent );
    procedure onmenuitemclick1( sender_ : TObject );
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.addMenuItem( popupmenu_ : TPopupMenu; caption_ : string; tag_ : integer; onClick_ : TNotifyEvent );
var
  menuitem1 : tmenuitem;
begin
  menuitem1 := tmenuitem.create( popupmenu_ );
  menuitem1.caption := caption_;
  menuitem1.Tag := tag_;
  menuitem1.onclick := onclick_;
  popupmenu_.items.add( menuitem1 );
end;

procedure TForm1.onmenuitemclick1( sender_ : TObject );
var
  id : integer;
begin
  id := tmenuitem( sender_ ).Tag;
  showmessage( 'menuitem.onclick called! (' + intToStr( id ) + ')' );
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  dynamicPopupMenu : tpopupmenu;
begin
  dynamicPopupMenu := tpopupmenu.create( self );
  try
    addMenuItem( dynamicPopupMenu, 'aaa', 1, onmenuitemclick1 );
    addMenuItem( dynamicPopupMenu, 'bbb', 2, onmenuitemclick1 );
    dynamicPopupMenu.popup( 500, 500 );
  finally
    dynamicPopupMenu.Free;
  end;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  staticPopupMenu.items.Clear;
  addMenuItem( staticPopupMenu, 'aaa', 1, onmenuitemclick1 );
  addMenuItem( staticPopupMenu, 'bbb', 2, onmenuitemclick1 );
  staticPopupMenu.popup( 500, 500 );
end;

end.

dfm：

object Form1: TForm1
  Left = 339
  Top = 270
  Caption = 'Form1'
  ClientHeight = 601
  ClientWidth = 854
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object Button1: TButton
    Left = 96
    Top = 128
    Width = 75
    Height = 25
    Caption = 'Button1'
    TabOrder = 0
    OnClick = Button1Click
  end
  object Button2: TButton
    Left = 177
    Top = 128
    Width = 75
    Height = 25
    Caption = 'Button2'
    TabOrder = 1
    OnClick = Button2Click
  end
  object staticPopupMenu: TPopupMenu
    Left = 280
    Top = 128
  end
end

标签： delphi

Answer 1

由于您正在dynamicPopupMenu使用当前TForm1实例创建您的实例Owner，因此我不确定您是否需要垃圾收集器的所有繁琐，因为TForm1实例本身被销毁时无论如何都会销毁它。

试试这个：

1. TComponent.Destroy在 Classes.Pas 中设置断点并在Tag.

2. Button1Click如下所示更改你的，禁用你的垃圾收集器，编译，运行并观察。

{代码}

procedure TForm1.Button1Click(Sender: TObject);
var
  dynamicPopupMenu : tpopupmenu;
  AForm : TForm;
begin
  AForm := TForm.Create(Nil);
  dynamicPopupMenu := tpopupmenu.create(AForm);
  try
    dynamicPOpUpMenu.Tag := 666;
    addMenuItem( dynamicPopupMenu, 'aaa', 1, onmenuitemclick1 );
    addMenuItem( dynamicPopupMenu, 'bbb', 2, onmenuitemclick1 );
    dynamicPopupMenu.popup( 600, 600 );
  finally
    AForm.Release;
  end;
end;