How to connect an object of any type using TControl?

Question

I want to add a TList with TTreeViewItem and a special class object (TRoom) with another. In delphi 2007 there was a “Data” field of type Pointer, which was replaced by TValue, in which I do not know how to use it. I searched the Internet, stating that it could not handle custom types yet.

Can anyone come up with a way to achieve this other than making a hack class?

For example, the following form code should work correctly: -

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Rtti, System.Classes,
  System.Variants, FMX.Types, FMX.Controls, FMX.Forms, FMX.Dialogs,
  FMX.TreeView, FMX.Layouts, FMX.Edit;

type
  TRoom = class

    ID : WORD;
    Name : String;

  end;

  TForm1 = class(TForm)
    TreeView1: TTreeView;
    TreeViewItem1: TTreeViewItem;
    Button1: TButton;
    Edit1: TEdit;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

procedure TForm1.Button1Click(Sender: TObject);
var
  List : TList;
begin

  // Get The List From TreeViewItem1
  // pani Solution  - List := TList ( TreeViewItem1.TagObject );

  Edit1.Text := TRoom ( List.First ).Name;

end;

procedure TForm1.FormCreate(Sender: TObject);
var
  Room : TRoom;
  List : TList;

begin

  List := TList.Create;
  Room := TRoom.Create;
  Room.ID := 5;
  Room.Name := IntToStr ( 5 );
  List.Add ( Room );

  // Add The List To TreeViewItem1    
  // pani Solution  - TreeViewItem1.TagObject := List;

end;

end.

Answer 1

If you want to "attach" an object to TControl, the TControl TFmxObject parent class introduces the .TagObject property, which stores any value of the object.

.Tag NativeInt , : TreeViewItem1.Tag: = NativeInt (List); List: = TList (TreeViewItem1.Tag);

Answer 2

"g" ' Data FMX . TImage , TEdit .. , Data VCL, .

pani, FMX, TagObject. , , FMX (. ), , TTreeViewItem:

uses System.Generics.Collections;

type
  TRoomTreeViewItem = class(TTreeViewItem)
    RoomList: TList<TRoom>; //better use a generic than non-generic list as mentioned above
  end;

, , , :

type
  TRoomTreeViewItem = class(TTreeViewItem)
  strict private
    FRoomList: TObjectList<TRoom>;
    function GetRoom(Index: Integer): TRoom;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    function GetEnumerator: TEnumerator<TRoom>;
    function AddRoom: TRoom;
    property Rooms[Index: Integer] read GetRoom;
  end;

constructor TRoomTreeViewItem.Create(AOwner: TComponent);
begin
  inherited;
  FRoomList := TObjectList<TRoom>.Create;
end;

destructor TRoomTreeViewItem.Destroy;
begin
  FRoomList.Free;
  inherited;
end;

function TRoomTreeViewItem.GetEnumerator: TEnumerator<TRoom>;
begin
  Result := FRoomList.GetEnumerator;
end;

function TRoomTreeViewItem.GetRoom(Index: Integer): TRoom;
begin
  Result := FRoomList[Index];
end;

function TRoomTreeViewItem.AddRoom: TRoom;
begin
  Result := TRoom.Create;
  FRoomList.Add(Result);
end;

- UI-, - (, ), YMMV.