Question

I have a popup menu in my listview which i would like as disabled when the click is not on any row, I would like to know on what event of ListView or PopupMenu should i do this.

Thanks in Advance

Answer 1

Handle the OnPopup event of the popup menu like this:

procedure TForm1.PopupMenu1Popup(Sender: TObject);
begin
  if ListView1.SelCount=0 then begin
    Abort;
  end;
end;

Don’t try and use the mouse cursor in your logic because the popup menu may be invoked from the keyboard.

---

It turns out that you want to disable certain items on the menu dependent on the selection. You should use actions for this and then you can centralise control of UI properties. An action can be linked to a button, a popup menu item, a main menu item and so on. You don’t want to write code that enables and disables all of these separately—actions solve this problem.

Use the OnUpdate event for this.

procedure TForm1.Action1Update(Sender: TObject);
begin
  Action1.Enabled := ListView1.SelCount>0;
end;

Or sometimes you want the same OnUpdate for many actions which you would code list this:

procedure TForm1.FileActionsUpdate(Sender: TObject);
begin
  (Sender as TAction).Enabled := ListView1.SelCount>0;
end;