那些 Cynthia 教我的事 之 PMSec (二)

一、在Foreach之前要判断是否为空。

常常从数据库里取出来表就直接用了，很少记得判断是否有值。不严谨的说。

专业人员写的是酱滴。。。

          DataLayer.PMSecDataSet.PMSECRequestDataTable requestDataTable = adapter.up_PMSec_PMSECRequestSelectByMasterIDs(masterIds);

          if (requestDataTable != null && requestDataTable.Count > 0)
          {
             ...
           }

二、当数据库中允许为空。

 话说，上次已经说过的啦。。。但是这次更加明确，要用Nullable<int>.

         Nullable<int> intNull = null;
          DataLayer.PMSecDataSet.PMSECRequestDataTable requestDataTable = adapter.up_PMSec_PMSECRequestSelectByMasterIDs(masterIds);

          if (requestDataTable != null && requestDataTable.Count > 0)
          {

              foreach (DataLayer.PMSecDataSet.PMSECRequestRow dr in requestDataTable.Rows)
              {
                  PMSecRequestInfo requestInfo = new PMSecRequestInfo();
                  requestInfo.RequestMasterID = dr.RequestMasterID;
                  requestInfo.EmployeeID = dr.EmployeeID;
                  Employee requestEmployee = new Employee(dr.EmployeeID);
                  requestInfo.DisplayName = requestEmployee.DisplayName;
                  requestInfo.StatusType = dr.StatusType;
                  requestInfo.CompanyID = dr.CompanyID;
                  requestInfo.WorkStoreID = dr.WorkStoreID;
                  requestInfo.JobCode = dr.JobCode;
                  requestInfo.RequestedSecurityLevel = dr.IsRequestedSecurityLevelNull() ? intNull : dr.RequestedSecurityLevel;
                  requestInfo.IsSecurityAdmin = dr.IsSecurityAdmin;
                  requestInfo.CreatedBy = dr.CreatedBy;
                  requestInfo.CreatedOn = dr.CreatedOn;

                  requestInfoList.Add(requestInfo);
              }
          }

string类无需此处理。

三、操作数据库时

当含有update等更改数据库内容的语句存在时，如果下面操作仍与数据库有关，考虑到程序的扩展性，可能出现上述语句删除了某些数据，下面语句出现异常，或者产生错误结果，等等。

譬如下面两段代码，前者是我的做法，后者为Cynthia的做法，一见高下啊啊啊。我写的好像是舒克和贝塔里那只笨猫，喵，~~~~(>_<)~~~~ 。

  public void ApporveOrDeclineRequest(string masterIds, string statusType, int loginEid)
      {
           PMSECRequestPendingTaskTableAdapter adapter = new PMSECRequestPendingTaskTableAdapter();
           adapter.up_PMSec_PMSECRequestUpdate(masterIds, statusType, loginEid);

          // Send Email
           PandaRG.Common.OrgChart.Employee logInEmployee = new Common.OrgChart.Employee(loginEid);

           if (statusType == RequestStatusType.APPROVED.ToString())
           {
               EmailSendHelper.SentEmailbyEmailType(RequestStatusType.APPROVED, GetRequestInfoListByRequestMasterIds(masterIds), logInEmployee);

           }
           else if(statusType==RequestStatusType.DECLINED.ToString())
           {
               EmailSendHelper.SentEmailbyEmailType(RequestStatusType.DECLINED, GetRequestInfoListByRequestMasterIds(masterIds), logInEmployee);
           }
      }

      public void UpdatePMSECRequest(string masterIds, RequestStatusType statusType, Employee loginEmployee)
      {
          PMSECRequestPendingTaskTableAdapter adapter = new PMSECRequestPendingTaskTableAdapter();

          List<PMSecRequestInfo> requestInfoList = GetRequestInfoListByRequestMasterIds(masterIds);
          adapter.up_PMSec_PMSECRequestUpdate(masterIds, statusType.ToString(), loginEmployee.EmployeeId);
          EmailSendHelper.SentEmailbyEmailType(statusType, requestInfoList, loginEmployee);  
      }

四、 λ 表达式

好复杂的说，不老明白的，计入λ 番外篇吧。

( ^_^ )/~~