LINQ中的外连接语句

我试图在LINQ中创建一个外部连接语句，但运气不太好。我知道执行外部联接需要两个步骤：

（1） 将联接转换为组联接，并将其转换为

（2） 如果联接的结果集为空，则对组使用DefaultIfEmpty（）生成所需的空值

我一直以这段代码为例：

var query = (from p in dc.GetTable<Person>()
join pa in dc.GetTable<PersonAddress>() on p.Id equals pa.PersonId into tempAddresses
from addresses in tempAddresses.DefaultIfEmpty()
select new { p.FirstName, p.LastName, addresses.State });

问题是intellisense无法识别select new{}语句中的任何内容。我试过你。甚至是字典

我可能遇到的问题是，我正在尝试连接两个词典。它似乎不喜欢这样，虽然这是我被告知我需要做的。我显然做错了什么，或者不理解什么

我需要将dictionary results.Unit与dictionary resultHours.Hours合并，因为在某些情况下，我的输出缺少unitId字段。做一个外部连接应该可以解决这个问题

以下是结果代码：

var results = 

    (from v in VDimUnit     
        join vf in VFactEnergyAllocation on v.UnitKey equals vf.UnitKey
        join vd in VDimGadsEvent on vf.GadsEventKey equals vd.GadsEventKey
        join vt in VDimTime on vf.TimeKey equals vt.TimeKey 
    where typeCodes.Contains(vd.GadsEventTypeCode)
    && vt.YearNum >= (year - 3) && vt.YearNum <= year       
    group vf by new {v.PlantId, v.PhysicalUnitId, v.NetDependableCapacity, v.NetMaximumCapacity, 
    vt.MonthNum} into groupItem     
    select new {groupItem.Key.PlantId, groupItem.Key.PhysicalUnitId, groupItem.Key.NetMaximumCapacity,
    groupItem.Key.MonthNum, PO_HRS = groupItem.Sum(
    x=> (float)x.AllocatedEnergyMwh / groupItem.Key.NetDependableCapacity),
            UO_HRS = groupItem.Sum(x=> (float)x.AllocatedEnergyMwh / groupItem.Key.NetDependableCapacity),
        Unit = groupItem.Count(), groupItem.Key}).ToDictionary(x=> x.Key, x=> x);

这就是我目前的产出情况。在我弄清楚如何进行外部连接后，它会发生变化

var finalResults = 

    (from r in results
    orderby r.Key.MonthNum, r.Key.PlantId, r.Key.PhysicalUnitId
    select new {Site = r.Key.PlantId, Unit = r.Key.PhysicalUnitId, r.Key.MonthNum, Numerator = r.Value.PO_HRS, Denominator = 
        resultHours[r.Key.ToString()], Weight = r.Key.NetMaximumCapacity, Data_Indicator = DATA_INDICATOR, 
        Budgeted = budgetedPlannedOutageHrs, Industry_Benchmark = INDUSTRY_BENCHMARK, Comments = comments, 
        Executive_Comments = executiveComments, Fleet_Exec_Comments = fleetExecComments});

---

我不知所措。我先前发现的LINQ外部联接示例在联接字典时不适用。

您不是在同一语句中混合使用Linq2Sql和Linq2Object，是吗？@Magnus:老实说，我不确定。我不这么认为。我会进一步研究的

var resultHours = 

    (from vt in VDimTime
        join vf in VFactEnergyAllocation on vt.TimeKey equals vf.TimeKey         
        join vd in VDimGadsEvent on vf.GadsEventKey equals vd.GadsEventKey
        join v in VDimUnit on vf.UnitKey equals v.UnitKey       

    group vt by new {v.PlantId, v.PhysicalUnitId, v.NetDependableCapacity, v.NetMaximumCapacity, 
        vt.MonthNum} into groupItem
    select new {groupItem.Key.PlantId, groupItem.Key.PhysicalUnitId, groupItem.Key.NetMaximumCapacity,
        Hours = groupItem.Count(), groupItem.Key}).ToDictionary(x=> x.Key.ToString(), x=> x.Hours); 

var finalResults = 

    (from r in results
    orderby r.Key.MonthNum, r.Key.PlantId, r.Key.PhysicalUnitId
    select new {Site = r.Key.PlantId, Unit = r.Key.PhysicalUnitId, r.Key.MonthNum, Numerator = r.Value.PO_HRS, Denominator = 
        resultHours[r.Key.ToString()], Weight = r.Key.NetMaximumCapacity, Data_Indicator = DATA_INDICATOR, 
        Budgeted = budgetedPlannedOutageHrs, Industry_Benchmark = INDUSTRY_BENCHMARK, Comments = comments, 
        Executive_Comments = executiveComments, Fleet_Exec_Comments = fleetExecComments});