콤보박스에서 대분류를 선택하면 추출이 되어서 다른 콤보박스에 내용이 들어가게 했는데 딱 한번만 되니 이게 어떻게 된건지 모르겠네여..
한번은 제대로 들어가는데 다시 대분류에서 다른 아이템을 선택하면 그내용 그대로이니 부탁드립니다.

다음은 쏘스입니다.

//시작할때 대분류에 아이템을 뿌려줍니다.
procedure TTradeF.FormCreate(Sender: TObject);
begin
  DateTimePicker1.Date := date;
  with qryLarge do begin
    close;
    sql.Clear;
    sql.Add('select LargeName');
    sql.Add('from LargeCode');
    open;
    while not EOF do begin
      cblarge.Items.add(FieldByName('largeName').AsString);
      next;
    end;
  end;

end;

//대분류 콤보박스의 아이템을 바꿀때마다 중분류 아이템이 바뀝니다.
procedure TTradeF.cblargeChange(Sender: TObject);

begin
if cblarge.itemindex > 0 then

  with qryMiddle do begin
    Case  cblarge.ItemIndex  of
   0 :   begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''A%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
   1:  begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''B%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    2 : begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''C%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    3 : begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''D%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    4 : begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''E%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    5 : begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''F%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    6 : begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''G%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    7 :  begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''H%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    8 : begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''I%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    9 : begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''J%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    10: begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''K%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    11: begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''L%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    12: begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''M%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    13: begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''N%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    14: begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''O%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin
    15: begin
         Close;
         sql.Clear;
         sql.add('select MiddleName');
         sql.add('from middlecode');
         sql.add('where 중코드 like ''P%''');
         open;
           While not EOF do begin
             cbmiddle.Items.add(FieldByName('middleName').AsString);
             next;
           end; //while
         end;//begin

    end;//case

    Close;
    Open;
    
  end; //with의 끝
END;