delphi - 弹出菜单没有出现在我的 Delphi 中

Question

表单上有 TPopupMenu 和三个名为“AddButton”、“EditButton”和“DestroyButton”的按钮，并向所有三个按钮添加了 OnClick 事件。窗体的 PopupMenu 属性中的 TPopupMenu。我在 TForm1 类型声明中创建了 PopupMenuItemsClick 过程，以便它可以用作菜单项 OnClick 事件的方法调用。

type
  TForm1 = class(TForm)
    AddButton: TButton;
    EditButton: TButton;
    DestroyButton: TButton;
    PopupMenu1: TPopupMenu;
    procedure AddButtonClick(Sender: TObject);
    procedure EditButtonClick(Sender: TObject);
    procedure DestroyButtonClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    procedure PopupMenuItemsClick(Sender: TObject);

  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.AddButtonClick(Sender: TObject);
var
  index: Integer;
  NewItem: TMenuItem;
begin
        // The owner (PopupMenu1) will clean up this menu item.
  NewItem := TMenuItem.Create(PopupMenu1); // Create the new item.
  index := PopupMenu1.Items.Count;
  PopupMenu1.Items.Add(NewItem);// Add it to the pop-up menu.
  NewItem.Caption := 'Menu Item ' + IntToStr(index);
  NewItem.Tag := index;
  NewItem.OnClick :=
    PopupMenuItemsClick; // Assign it an event handler.
end;

procedure TForm1.PopupMenuItemsClick(Sender: TObject);
begin
  with Sender as TMenuItem do
  begin
    case Tag of
      0:  ShowMessage('first item clicked');
      1:  ShowMessage('second item clicked');
      2:  ShowMessage('third item clicked');
      3:  ShowMessage('fourth item clicked');
    end;
  end;
end;

{
To edit or destroy an item, grab its pointer 
using the Items property.
procedure TForm1.EditButtonClick(Sender: TObject);
var
  ItemToEdit: TMenuItem;
begin
  ItemToEdit := PopupMenu.Items[1];
  ItemToEdit.Caption := 'Changed Caption';
end;

procedure TForm1.DestroyButtonClick(Sender: TObject);
var
  ItemToDelete: TMenuItem;
begin
  ItemToDelete := PopupMenu.Items[2];
  ItemToDelete.Free;
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  index: Integer;
  NewItem: TMenuItem;
begin
  for index := 0 to 3 do
  begin
          // The owner (PopupMenu1) will clean up this menu item.
    NewItem := TMenuItem.Create(PopupMenu1); // Create the new item.
    PopupMenu1.Items.Add(NewItem);// Add it to the pop-up menu.
    NewItem.Caption := 'Menu Item ' + IntToStr(index);
    NewItem.Tag := index;
    NewItem.OnClick :=
      PopupMenuItemsClick; // Assign it an event handler.
  end;
end;

但是当我单击添加菜单按钮时，弹出菜单没有出现。任何人都可以找到加载表单或单击任何按钮时未出现 Popupmenu 的原因。

Answer 1

你的代码不是你真正需要的使用此代码，它将完美运行

procedure TForm1.PopupMenuItemsClick(Sender: TObject);
  var ICount : Integer;
begin
  ICount := TMenuItem(Sender).MenuIndex;
  ShowMessage('Item Number '+ IntToStr(ICount+1) + ' Selected');
end;

procedure TForm1.AddClick(Sender: TObject);
  var
    Index: Integer;
    NewItem: TMenuItem;
begin
    NewItem := TMenuItem.Create(PopupMenu);
    Index := PopupMenu.Items.Count;
    PopupMenu.Items.Add(NewItem);
    NewItem.Caption := 'Menu Item ' + IntToStr(Index);
    NewItem.Tag := Index;
    NewItem.OnClick := PopupMenuItemsClick;
    PopupMenu.Popup(Mouse.CursorPos.X, Mouse.CursorPos.Y);
end;

我用 Delphi7、XE2 和 XE3 测试了它的工作