如果FetchXML(AGGREGATE SUM)查询未找到任何内容，那么EntityCollection返回什么? [英] What does EntityCollection return if FetchXML (AGGREGATE SUM) Query didn't find anything?
本文介绍了如果FetchXML(AGGREGATE SUM)查询未找到任何内容，那么EntityCollection返回什么?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在运行一个FetchXML查询(对于fetch来说为aggregate ='true'，对于所有属性来说是aggregate ='sum')，并将其传递给我的C#插件代码中的RetreiveMultiple.如果Fetchxml找不到任何东西，在这种情况下service.RetrieveMultiple会检索什么呢? 在调试器中，存在NullReference异常.
I am running a FetchXML query (aggregate='true' for the fetch and aggregate='sum' for all attributes) and passing it to RetreiveMultiple in my C# plugin code. What if the Fetchxml didn't find anything, what does service.RetrieveMultiple retrieve in this case? In the debugger, there is a NullReference exception.
FetchXML Builder返回以下内容:
FetchXML Builder returns this:
我需要处理合同中缺少一餐的情况...在我的插件中，我有三个Fetchxml表达式，它们从合同中的实体中检索数据(一天中每顿饭，一个用于AM SNACKS /LUNCH/PM零食).如果FetchXMl实体之一没有要检索的数据，则插件根本不会产生任何东西...即使其中一个FetchXML查询返回了一些结果.三个FETCHXML查询中的任何一个... 请注意，如果我在合同行中包含所有三餐，则插件工作正常！这是我的代码:
I need to handle a case where one of the meals in the contract lines is missing... In my plugin I have three Fetchxml expressions that Retrieve data from the contract lines entity (One for each meal of the day, AM SNACKS/LUNCH/PM SNACKS). If one of the FetchXMl entities doesn't have data to retrieve, the plugin does not produce anything at all... even though one of the FetchXML queries returned some results.. I simply want to place zeros whenever there is no data returned from anyone of the three FETCHXML Queries... PLEASE NOTE THAT IF I INCLUDE ALL THREE MEALS IN THE CONTRACT LINES, THE PLUGIN WORKS FINE!! Here is my code:
try
{
//Get Contract StartDate
DateTime startDate = (DateTime)PreImage["activeon"];
//Get Contract EndDate
DateTime endDate = (DateTime)PreImage["expireson"];
//Create an instance of the range class
Eachday range = new Eachday();
//use Weekday method of range class to get a weekdays list
var weekdays = range.WeekDay(startDate, endDate);
//Get Contract Number
string contractNumber = (string)PreImage["contractnumber"];
//Get Unit Order Lookup Id
EntityReference unitOrder = (EntityReference)PreImage.Attributes["new_unitorderid"];
var unitOrderId = unitOrder.Id;
//Query and aggregate each Weekday's order for the 3 different meal times...
//AM SNACK FetchXML Query.. string is passed to service.RetrieveMultiple();
string unitsum_am = @" <fetch aggregate='true' distinct='false' >
<entity name='contract' >
<link-entity name='contractdetail' from = 'contractid' to = 'contractid' >
<attribute name='new_mondayunits' alias='new_mondayunits_amsum' aggregate='sum' />
<attribute name='new_tuesdayunits' alias='new_tuesdayunits_amsum' aggregate='sum' />
<attribute name='new_unitswednesday' alias='new_unitswednesday_amsum' aggregate='sum' />
<attribute name='new_unitsthursday' alias='new_unitsthursday_amsum' aggregate='sum' />
<attribute name='new_unitsfriday' alias='new_unitsfriday_amsum' aggregate='sum' />
<filter type='and' >
<condition value='100000001' attribute='new_servingtime' operator= 'eq' />
<condition value='0' attribute='statecode' operator= 'eq' />
<condition value='" + targetId + @"' attribute='contractid' operator= 'eq' />
</filter >
</link-entity>
</entity >
</fetch>";
//Retrieve a collection of records
EntityCollection unitsum_am_result =
service.RetrieveMultiple(new FetchExpression(unitsum_am));
//AM SNACKS list for the week
var am_list = new List<int>();
//iterate through all records and get the sum for each day
//place the sums into the am_list
if (unitsum_am_result.Entities.Count == 0)
{
am_list.AddRange(Enumerable.Repeat(0, 5));
}
else
{
foreach (var unit in unitsum_am_result.Entities)
{
var mondaysum = ((int)((AliasedValue)unit["new_mondayunits_amsum"]).Value);
am_list.Add(mondaysum);
var tuesdaysum = ((int)((AliasedValue)unit["new_tuesdayunits_amsum"]).Value);
am_list.Add(tuesdaysum);
var wednesdaysum = ((int)((AliasedValue)unit["new_unitswednesday_amsum"]).Value);
am_list.Add(wednesdaysum);
var thursdaysum = ((int)((AliasedValue)unit["new_unitsthursday_amsum"]).Value);
am_list.Add(thursdaysum);
var fridaysum = ((int)((AliasedValue)unit["new_unitsfriday_amsum"]).Value);
am_list.Add(fridaysum);
}
}
//LUNCH FetchXML Query.. string is passed to service.RetrieveMultiple();
string unitsum_lunch = @" <fetch aggregate='true' distinct='false' >
<entity name='contract' >
<link-entity name='contractdetail' from = 'contractid' to = 'contractid' >
<attribute name='new_mondayunits' alias='new_mondayunits_lunchsum' aggregate='sum' />
<attribute name='new_tuesdayunits' alias='new_tuesdayunits_lunchsum' aggregate='sum' />
<attribute name='new_unitswednesday' alias='new_unitswednesday_lunchsum' aggregate='sum' />
<attribute name='new_unitsthursday' alias='new_unitsthursday_lunchsum' aggregate='sum' />
<attribute name='new_unitsfriday' alias='new_unitsfriday_lunchsum' aggregate='sum' />
<filter type='and' >
<condition value='100000002' attribute='new_servingtime' operator= 'eq' />
<condition value='0' attribute='statecode' operator= 'eq' />
<condition value='" + targetId + @"' attribute='contractid' operator= 'eq' />
</filter >
</link-entity>
</entity >
</fetch>";
//Retrieve a collection of records
EntityCollection unitsum_lunch_result =
service.RetrieveMultiple(new FetchExpression(unitsum_lunch));
//Lunch meals list for the week
var lunch_list = new List<int>();
//iterate through all records and get the sum for each day
//place the sums into the lunch_list
if (unitsum_lunch_result.Entities.Count == 0)
{
lunch_list.AddRange(Enumerable.Repeat(0, 5));
}
else
{
foreach (var unit in unitsum_lunch_result.Entities)
{
var mondaysum = ((int)((AliasedValue)unit["new_mondayunits_lunchsum"]).Value);
lunch_list.Add(mondaysum);
var tuesdaysum = ((int)((AliasedValue)unit["new_tuesdayunits_lunchsum"]).Value);
lunch_list.Add(tuesdaysum);
var wednesdaysum = ((int)((AliasedValue)unit["new_unitswednesday_lunchsum"]).Value);
lunch_list.Add(wednesdaysum);
var thursdaysum = ((int)((AliasedValue)unit["new_unitsthursday_lunchsum"]).Value);
lunch_list.Add(thursdaysum);
var fridaysum = ((int)((AliasedValue)unit["new_unitsfriday_lunchsum"]).Value);
lunch_list.Add(fridaysum);
}
}
//PM SNACK FetchXML Query.. string is passed to service.RetrieveMultiple();
string unitsum_pm = @" <fetch aggregate='true' distinct='false' >
<entity name='contract' >
<link-entity name='contractdetail' from = 'contractid' to = 'contractid' >
<attribute name='new_mondayunits' alias='new_mondayunits_pmsum' aggregate='sum' />
<attribute name='new_tuesdayunits' alias='new_tuesdayunits_pmsum' aggregate='sum' />
<attribute name='new_unitswednesday' alias='new_unitswednesday_pmsum' aggregate='sum' />
<attribute name='new_unitsthursday' alias='new_unitsthursday_pmsum' aggregate='sum' />
<attribute name='new_unitsfriday' alias='new_unitsfriday_pmsum' aggregate='sum' />
<filter type='and' >
<condition value='100000003' attribute='new_servingtime' operator= 'eq' />
<condition value='0' attribute='statecode' operator= 'eq' />
<condition value='" + targetId + @"' attribute='contractid' operator= 'eq' />
</filter >
</link-entity>
</entity >
</fetch>";
//Retrieve a collection of records
EntityCollection unitsum_pm_result =
service.RetrieveMultiple(new FetchExpression(unitsum_pm));
//PM SNACK list for the week
var pm_list = new List<int>();
//iterate through all records and get the sum for each day
//place the sums into the pm_list
if (unitsum_pm_result.Entities.Count == 0)
{
pm_list.AddRange(Enumerable.Repeat(0, 5));
}
else
{
foreach (var unit in unitsum_pm_result.Entities)
{
var mondaysum = ((int)((AliasedValue)unit["new_mondayunits_pmsum"]).Value);
pm_list.Add(mondaysum);
var tuesdaysum = ((int)((AliasedValue)unit["new_tuesdayunits_pmsum"]).Value);
pm_list.Add(tuesdaysum);
var wednesdaysum = ((int)((AliasedValue)unit["new_unitswednesday_pmsum"]).Value);
pm_list.Add(wednesdaysum);
var thursdaysum = ((int)((AliasedValue)unit["new_unitsthursday_pmsum"]).Value);
pm_list.Add(thursdaysum);
var fridaysum = ((int)((AliasedValue)unit["new_unitsfriday_pmsum"]).Value);
pm_list.Add(fridaysum);
}
}
//iterate through entire contract duration
foreach(var day in weekdays)
{
Entity alterunit = new Entity("new_alterunitorder"); //create new alter unit record
alterunit.Attributes.Add("new_orderdate", DateTime.Parse(day)); //set the day field
var currentday = day.Split(',')[0]; //current day
switch (currentday)
{
case "Monday":
alterunit.Attributes.Add("new_amsnack", am_list[0]); //set the total am snacks
alterunit.Attributes.Add("new_lunch", lunch_list[0]); //set the total lunch meals
alterunit.Attributes.Add("new_pmsnack", pm_list[0]); //set the total pm snacks
break;
case "Tuesday":
alterunit.Attributes.Add("new_amsnack", am_list[1]);
alterunit.Attributes.Add("new_lunch", lunch_list[1]);
alterunit.Attributes.Add("new_pmsnack", pm_list[1]);
break;
case "Wednesday":
alterunit.Attributes.Add("new_amsnack", am_list[2]);
alterunit.Attributes.Add("new_lunch", lunch_list[2]);
alterunit.Attributes.Add("new_pmsnack", pm_list[2]);
break;
case "Thursday":
alterunit.Attributes.Add("new_amsnack", am_list[3]);
alterunit.Attributes.Add("new_lunch", lunch_list[3]);
alterunit.Attributes.Add("new_pmsnack", pm_list[3]);
break;
case "Friday":
alterunit.Attributes.Add("new_amsnack", am_list[4]);
alterunit.Attributes.Add("new_lunch", lunch_list[4]);
alterunit.Attributes.Add("new_pmsnack", pm_list[4]);
break;
default:
Console.WriteLine($"An unexpected value ({currentday})");
break;
}
alterunit.Attributes.Add("new_name", contractNumber); //set the record name
//set the unit order record relation
alterunit.Attributes["new_orderlineid"] =
new EntityReference("new_units", unitOrderId);
service.Create(alterunit); //create the record
}
}
这是调试的结果:
第190行还引发了一个异常:
There is also an Exception thrown on line 190:
推荐答案
实际上，实体集合会返回完全合格的EntityCollection，而实体计数将为零.但是，似乎在使用聚合'sum'时，如果集合为空，则平台将引发错误. 计数"不会发生这种情况.为了解决这个问题，我做到了:
The entity collection does in fact return a fully qualified EntityCollection and the entity count will be zero. HOWEVER, It seems that when using the aggregate 'sum', if the collection is empty the platform throws an error. It doesn't happen with 'count'. To fix it, I did:
//iterate through all records and get the sum for each day
//place the sums into the am_list
foreach(var unit in unitsum_am_result.Entities)
{
try
{
am_list.Add(((int)((AliasedValue)unit["new_mondayunits_amsum"]).Value));
am_list.Add(((int)((AliasedValue)unit["new_tuesdayunits_amsum"]).Value));
am_list.Add(((int)((AliasedValue)unit["new_unitswednesday_amsum"]).Value));
am_list.Add(((int)((AliasedValue)unit["new_unitsthursday_amsum"]).Value));
am_list.Add(((int)((AliasedValue)unit["new_unitsfriday_amsum"]).Value));
}
catch
{
am_list.AddRange(Enumerable.Repeat(0, 5));
}
}
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