unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;type
  TForm1 = class(TForm)
    ListBox1: TListBox;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;
  count1:Integer;
 // a,b,c:Integer;implementation{$R *.dfm}procedure TForm1.Button1Click(Sender: TObject);
begin
count1:=count1+1;
if (count1 mod 2=1) then
ListBox1.Items.Add('HELLO WORLD!');
else
ListBox1.Items.Add('HELLO FRIEND!');
end;end.
后面的判断,我分别注释后都能显示出来,但是放一起就会报错。请问原因。Delphi