Right-click doesn't update ItemIndex in TControlList - delphi

Question

I've added a TPopupMenu to a TControlList, on right-click the ItemIndex isn't updated to reflect the item clicked on. Is there a way to make a right-click respond in a similar way to a left-click?
This would be nice so that the user right-clicks on a particular item, the PopupMenu is associated with that item, not the currently focused item.

Answer 1

You can use HotItemIndex property from OnPopupMenu event and save it to a variable. Then for the popup menu items events you can use it.
Example code:
unit Unit1;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.Menus, Vcl.ControlList, Vcl.StdCtrls;
type
TForm1 = class(TForm)
ControlList1: TControlList;
PopupMenu1: TPopupMenu;
TestPopupMnu: TMenuItem;
Label1: TLabel;
Memo1: TMemo;
procedure ControlList1BeforeDrawItem(AIndex: Integer; ACanvas: TCanvas; ARect:
TRect; AState: TOwnerDrawState);
procedure ControlList1Click(Sender: TObject);
procedure TestPopupMnuClick(Sender: TObject);
procedure PopupMenu1Popup(Sender: TObject);
private
FPopupItemIndex : Integer;
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.ControlList1BeforeDrawItem(AIndex: Integer; ACanvas: TCanvas;
ARect: TRect; AState: TOwnerDrawState);
begin
Label1.Caption := AIndex.ToString;
end;
procedure TForm1.ControlList1Click(Sender: TObject);
begin
Memo1.Lines.Add('Clicked item ' + ControlList1.ItemIndex.ToString);
end;
procedure TForm1.TestPopupMnuClick(Sender: TObject);
begin
Memo1.Lines.Add('Test PopupMenu item ' + FPopupItemIndex.ToString);
end;
procedure TForm1.PopupMenu1Popup(Sender: TObject);
begin
FPopupItemIndex := ControlList1.HotItemIndex;
end;
end.
The form itself:
object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 299
ClientWidth = 635
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
PixelsPerInch = 96
TextHeight = 13
object ControlList1: TControlList
Left = 24
Top = 20
Width = 317
Height = 200
ItemCount = 5
ItemMargins.Left = 0
ItemMargins.Top = 0
ItemMargins.Right = 0
ItemMargins.Bottom = 0
ParentColor = False
PopupMenu = PopupMenu1
TabOrder = 0
OnBeforeDrawItem = ControlList1BeforeDrawItem
OnClick = ControlList1Click
object Label1: TLabel
Left = 92
Top = 20
Width = 31
Height = 13
Caption = 'Label1'
end
end
object Memo1: TMemo
Left = 368
Top = 24
Width = 241
Height = 201
Lines.Strings = (
'Memo1')
TabOrder = 1
end
object PopupMenu1: TPopupMenu
OnPopup = PopupMenu1Popup
Left = 436
Top = 128
object TestPopupMnu: TMenuItem
Caption = 'Test'
OnClick = TestPopupMnuClick
end
end
end

Answer 2

In order to handle Right Clicks you will have to make use of OnMouseDown or OnMouseUp events instead of OnClick event.
Unlike OnClick event that only detects left clicks OnMouseDown and OnMouseUp events are able to detect all mouse clicks (left, right, middle).
procedure TForm1.ControlList1MouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
if Button = mbRight then
begin
//Do what needs to be done on right click
end
else if Button = mbMiddle then
begin
//Do what needs to be done on middle click
end
end;

Answer 3

The HotItemIndex property can be used to detect which item has been right-clicked by using the following
procedure TListingList.clListingsMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
inherited;
if Button <> mbRight then
Exit;
if clListings.HotItemIndex <> -1 then
clListings.ItemIndex := clListings.HotItemIndex;
end;
This mostly works, but if you already have a TPopupmenu visible already, then the HotItemIndex is -1. This means that consecutive right-clicks don't popup for the correct item - but I can live with this. I think a MousePosToItemIndex or ItemIndexUnderMouse method would be required to fix this properly.