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這裏是我的查詢:LINQ到SQL:如果連接條件左手邊等於NULL,對象引用異常被拋出
from f in DataAccess.Data.FList
join fA in DataAccess.Data.FAppsList on f.ID equals fA.fID into fApps
from fA in fApps.Where(fA => fA.Year == reportYear).DefaultIfEmpty()
join fSrc in DataAccess.Data.FSourcesList on new { ID = fA.sourceID, CropYear = reportYear }
equals new { ID = fSrc.ID, CropYear = fSrc.CropYear }
我得到的對象引用空異常如fa == NULL。我在fA上做了一個左連接,因此它可以是null或非null值。如何重寫這部分查詢,以便查詢在fA爲空時不會引發異常。
非常感謝!
非常感謝。有效! – Aqua267