偶用这段代码修改checklistbox所代表的权限，权限用字符串表达，但是运行时总是报错：dataset is not in edit or insert,好奇怪

Question

    query4.close;
    query4.parambyname('name').value:=dbedit1.text;
    query4.open;
if query4.recordcount=1 then
begin
  query4.Edit;
  query4.FieldByName('qx').asstring:='';
  query4.Post;
end;
      qxs:='';
        for i:=0 to CheckListBox2.Items.Count-1 do
      if CheckListBox1.Checked[i] then
        qxs:='1'+qxs
      else
        qxs:='0'+qxs;
    data.tbl_pass.edit;
    data.tbl_pass.fieldbyname('qx').asstring:=qxs;
    data.tbl_pass.Post;