Unit Unit1;

Interface

Uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ComCtrls, ExtCtrls;

Type myPanel = Class(TPanel)
  PRIVATE
    FTreeView: TTreeView;
  PUBLIC
    Constructor Create(AOwner: TComponent); OVERRIDE;
  End;

Type
  TForm1 = Class(TForm)
    Procedure FormCreate(Sender: TObject);
  PRIVATE
    FMyPanel: myPanel;
  PUBLIC

  End;

Var
  Form1: TForm1;

Implementation

{$R *.dfm}

Procedure TForm1.FormCreate(Sender: TObject);
Begin
  FMyPanel := myPanel.Create(Self);
End;

{ myPanel }

Constructor myPanel.Create(AOwner: TComponent);
Begin
  Inherited;
  FTreeView := TTreeView.Create(Self);
  FTreeView.Parent := Self;
  FTreeView.Align := alClient;
  FTreeView.Items.AddNode(Nil, Nil, 'test', Nil, naAdd);
End;

End.