delphi数据库相关

下面的FromShow事件里的change:=false 说无法识别change 是怎么回事啊！！这不是
关键字段自带的吗？？？应该不需要声明该变量吧！！  到底怎么回事？？？？帮帮忙
这个不解决后面的窗体就无法创建了！！！急！！！！！unit Unit1_f_kcsp;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Unit1_f_base, DB, ADODB, StdCtrls, ExtCtrls, Grids, DBGrids,
  ComCtrls, Buttons, ToolWin;type
  TF_kcsp = class(TF_base)
    ToolBar1: TToolBar;
    BitBtn1: TBitBtn;
    ToolButton1: TToolButton;
    ToolButton2: TToolButton;
    BitBtn2: TBitBtn;
    ToolButton3: TToolButton;
    BitBtn3: TBitBtn;
    BitBtn4: TBitBtn;
    ToolButton4: TToolButton;
    ToolButton5: TToolButton;
    BitBtn5: TBitBtn;
    ToolButton6: TToolButton;
    BitBtn6: TBitBtn;
    ToolButton7: TToolButton;
    DBGrid1: TDBGrid;
    Panel1: TPanel;
    GroupBox1: TGroupBox;
    Label1: TLabel;
    Label2: TLabel;
    Edit1: TEdit;
    ComboBox1: TComboBox;
    DataSource1: TDataSource;
    ADOQuery1: TADOQuery;    procedure BitBtn1Click(Sender: TObject);
    procedure BitBtn3Click(Sender: TObject);
    procedure BitBtn4Click(Sender: TObject); 
    procedure FormShow(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  F_kcsp: TF_kcsp;implementation
uses unit1_f_sbjbcx;
{$R *.dfm}procedure TF_kcsp.BitBtn1Click(Sender: TObject);
begin
  inherited;
  change:=false;
  application.createform(TF_sbjbcx,F_sbjbcx);
  f_sbjbcx.ShowModal;
  f_sbjbcx.Free;
end;procedure TF_kcsp.BitBtn3Click(Sender: TObject);
begin
  inherited;
   try
    if application.messagebox('是否删除数据','提示',mb_yesno)=id_yes then
     adoquery1.Delete;
  except
      application.MessageBox('不能删除该数据','提示',mb_yesno);
      end;
end;procedure TF_kcsp.BitBtn4Click(Sender: TObject);
var
   searchwhat:string;
begin
  inherited;
   panel1.Visible:=not(panel1.visible);
  if panel1.Visible=false then
  begin
     searchwhat:='';
    case combobox1.ItemIndex of
     0:searchwhat:='tradecode';
     1:searchwhat:='fullname';
     2:searchwhat:='name';
     3:searchwhat:='shortcode';
     end;
     try
     with adoquery1 do
     begin
        close;
        sql.Clear;
        sql.Add('select * from tb_stock');
        sql.Add('where''+searchwhat+'+'like :a order by tradecode');
        parameters.ParamByName('a').value:='%'+trim(edit1.text)+'%';
        open;
     end;
     if application.MessageBox('是否刷新表','提示',mb_yesno)=id_yes then
     with adoquery1 do
     begin
      close;
      sql.Clear;
      sql.Add('select * from tb_stock order by tradecode');
      open;
     end;
     except
      application.MessageBox('请正确输入条件','提示',mb_ok);
      end; end;
end;procedure TF_kcsp.FormShow(Sender: TObject);
begin
  inherited;
  change:=false; 
  with adoquery1 do
  begin
    close;
    sql.Clear;
    sql.Add('select * from tb_stock order by tradecode asc');
    open;
    end;end;end.unit Unit1_f_base;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ActnList, ToolWin, ActnMan, ActnCtrls, XPStyleActnCtrls,
  ComCtrls, StdCtrls, ExtCtrls, Buttons, jpeg;type
  TF_base = class(TForm)
    procedure FormKeyPress(Sender: TObject; var Key: Char);
    procedure FormKeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  F_base: TF_base;implementation{$R *.dfm}
procedure TF_base.FormKeyPress(Sender: TObject; var Key: Char);
begin
    if key=#13 then
      perform(wm_nextdlgctl,0,0);
end;procedure TF_base.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
    if key=vk_F5 then
      close;
end;end.