CheckBox控件默认选中,提交时永远获得选中状态的

//加班设置数据绑定
protected void CheckBoxBind()
  {
    OverTimeBLL overTimeBll = new OverTimeBLL();
    List<OverTime> overTimeList = new List<OverTime>();

    overTimeList = overTimeBll.GetAll();
    if (overTimeList.Count > 0)
    {
      //绑定页面信息
      txtID.Text = overTimeList[0].ID.ToString();
      if (overTimeList[0].IsEarlyValid.ToLower() == "true") cbIsEarlyValid.Checked = true;
      if (overTimeList[0].IsLaterValid.ToLower() == "true") cbIsLaterValid.Checked = true;
      if (overTimeList[0].IsOnlyHoliday.ToLower() == "true") cbIsOnlyHoliday.Checked = true;
      if (overTimeList[0].IsUseTime.ToLower() == "true") cbIsUseTime.Checked = true;
      if (overTimeList[0].IsUseNum.ToLower() == "true") cbIsUseNum.Checked = true;
      txtMinDuration.Text = overTimeList[0].MinDuration.ToString();
    }
  }

if (!this.Page.IsPostBack)
      {
        remindResult.Text = GetRemind();
        //页面数据绑定
        CheckBoxBind();
      }