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我是新來使用LINQ to SQL和我有一個問題LINQ到1 SQL預先加載到許多和多對多的關係船舶
這是我的模型的一部分:
- 訪問> VisitProduct <產品
- 訪問> VisitSample <產品
- 訪問> VisitStatus
我想加載所有相關實體的訪問實體,但它給了我一個「InvalidCastexception」。 ,我用這個代碼:(?我不知道爲什麼發生這種情況)
using (TeamsExcellenceDataContext context = new TeamsExcellenceDataContext())
{
DataLoadOptions lo = new DataLoadOptions();
context.DeferredLoadingEnabled = false;
lo.LoadWith<Visit>(v => v.Visitstatus);
lo.LoadWith<Visit>(v => v.VisitProducts);
lo.LoadWith<Visit>(v => v.VisitSamples);
context.LoadOptions = lo;
var temp = (from v in context.Visits
where v.VisitID == visitID
select v).Single();
Visit v = temp;
}
生成的SQL語句被分成兩個部分:
SELECT [t0].[VisitID], [t0].[StartDate], [t0].[EndDate], [t0].[TypeID], [t0].[StatusID], [t0].[NextObjective], [t0].[CpFeedback], [t0].[Feedback], [t0].[AccID], [t0].[CustMPID], [t0].[AccTreeID], [t0].[RepPermitDays], [t0].[ModeTypeID], [t0].[Recurrence], [t0].[RecurrenceParentKey], [t0].[CDate], [t2].[VisitID] AS [VisitID2], [t2].[ProductID], [t2].[VisitProductTurn], [t2].[CDate] AS [CDate2], (
SELECT COUNT(*)
FROM [dbo].[VisitProducts] AS [t3]
WHERE [t3].[VisitID] = [t0].[VisitID]
) AS [value], [t1].[VisitStatusID], [t1].[VisitStatusName], [t1].[VisitStatusMarker], [t1].[CDate] AS [CDate3]
FROM [dbo].[Visits] AS [t0]
INNER JOIN [dbo].[Visitstatus] AS [t1] ON [t1].[VisitStatusID] = [t0].[StatusID]
LEFT OUTER JOIN [dbo].[VisitProducts] AS [t2] ON [t2].[VisitID] = [t0].[VisitID]
WHERE [t0].[VisitID] = @p0
ORDER BY [t0].[VisitID], [t1].[VisitStatusID], [t2].[ProductID]
-- @p0: Input Int (Size = -1; Prec = 0; Scale = 0) [411]
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 4.0.30319.1
SELECT [t0].[VisiteID], [t0].[ProductID], [t0].[SampleQuantity], [t0].[CDate]
FROM [dbo].[VisitSamples] AS [t0]
WHERE [t0].[VisiteID] = @x1
-- @x1: Input Int (Size = -1; Prec = 0; Scale = 0) [411]
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 4.0.30319.1/
的異常不會不會發生如果我省略這一行:
lo.LoadWith<Visit>(v => v.Visitstatus);
或任何這些線路的
lo.LoadWith<Visit>(v => v.VisitSamples);
lo.LoadWith<Visit>(v => v.VisitProducts);
我做錯了什麼或我該如何解決此問題?
然後你應該在你的模型中使用字節而不是int。 TinyInt轉換爲字節。 – 2012-04-24 06:52:54