Project Structure

• HideComp.dpr
• HideForm.pas
• HideForm.dfm

program HideComp;

uses
  Forms,
  HideForm in 'HideForm.pas' {Form1};

{$R *.RES}

begin
  Application.Initialize;
  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.

unit HideForm;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    procedure Button1Click(Sender: TObject);
    procedure Edit1Change(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    Button1: TButton;
    Edit1: TEdit;
    ListBox1: TListBox;
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
begin
  ListBox1.Items.Add (Edit1.Text);
end;

procedure TForm1.Edit1Change(Sender: TObject);
begin
  Button1.Enabled := Length (Edit1.Text) <> 0;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Button1 := FindComponent ('Button1') as TButton;
  Edit1 := FindComponent ('Edit1') as TEdit;
  ListBox1 := FindComponent ('ListBox1') as TListBox;
end;

initialization
  RegisterClasses ([TButton, TEdit, TListBox]);
end.

object Form1: TForm1
  Left = 238
  Top = 107
  Width = 252
  Height = 233
  Caption = 'HideComp'
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'MS Sans Serif'
  Font.Style = []
  OldCreateOrder = False
  OnCreate = FormCreate
  PixelsPerInch = 96
  TextHeight = 13
  object Button1: TButton
    Left = 152
    Top = 24
    Width = 73
    Height = 23
    Caption = 'Add'
    Enabled = False
    TabOrder = 0
    OnClick = Button1Click
  end
  object Edit1: TEdit
    Left = 16
    Top = 24
    Width = 121
    Height = 21
    TabOrder = 1
    OnChange = Edit1Change
  end
  object ListBox1: TListBox
    Left = 16
    Top = 56
    Width = 209
    Height = 129
    ItemHeight = 13
    TabOrder = 2
  end
end