如果FetchXML（AGGREGATE SUM）查询未找到任何内容，那么EntityCollection返回什么？
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？ 在调试器中，存在NullReference异常。
FetchXML Builder返回以下内容：
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 /午餐/下午零食）。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。.我只是想在没有数据返回的情况下放置零。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：
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行也引发了异常：
3 个答案:
答案 0 :(得分：1)
它将返回完全限定的EntityCollection，但是Entities属性在集合中将有零个记录。
答案 1 :(得分：0)
既不为null也不为空。
您可以使用以下代码段识别结果集：
if (unitsum_am_result.Entities.Count == 0)
{
am_list.AddRange(Enumerable.Repeat(0, 5));
}
else
{
//foreach....
}
答案 2 :(得分：0)
实际上，实体集合会返回完全合格的EntityCollection，并且实体计数将为零。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：
//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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