LINQ編譯的查詢將不會執行 - ArgumentNulException未處理

Question

我正在測試編譯查詢的第一次。

我當前的查詢是：

Shared compiledLatestDate As Func(Of RackJobbingDataDataContext, ArtikelInfoParameters, List(Of VerdelingPlanning)) = _ 
    CompiledQuery.Compile(Of RackJobbingDataDataContext, ArtikelInfoParameters, List(Of VerdelingPlanning))(_ 
     Function(db As RackJobbingDataDataContext, param As ArtikelInfoParameters) _ 
      (From verdplan As VerdelingPlanning In db.VerdelingPlannings _ 
      Join artPlan As ArtikelPlanning In db.ArtikelPlannings _ 
      On artPlan.VerdelingPlanningID Equals verdplan.VerdelingPlanningID _ 
      Join levDet As LeveringDetail In db.LeveringDetails _ 
      On levDet.ArtikelPlanningID Equals artPlan.ArtikelPlanningID _ 
      Join lev As Levering In db.Leverings _ 
      On lev.LeveringID Equals levDet.LeveringID _ 
      Where artPlan.ArtikelID.Equals(param.artId) _ 
      And lev.WinkelID.Equals(param.winkId) _ 
      And Not levDet.PlanningAantal.Equals(Nothing) _ 
      And levDet.PlanningAantal <> 0 _ 
      And verdplan.Datum < param.datumVerdeling _ 
      Order By verdplan.Datum Descending _ 
     Select levDet)) 

但是我收到一個ArgumentNulException了未處理。

委員會獲悉了LINQ查詢與所需的參數添加對象，所以這是類：

Public Class ArtikelInfoParameters 
Private _wkId As Guid 
Private _artId As Guid 
Private _datumVerdeling As DateTime 
Public Sub New(ByVal artId As Guid, ByVal winkId As Guid, ByVal datumVerdeling As DateTime) 
    _artId = artId 
    _wkId = winkId 
    _datumVerdeling = datumVerdeling 
End Sub 
Public Property artId As Guid 
    Get 
     Return _artId 
    End Get 
    Set(ByVal value As Guid) 
     _artId = value 
    End Set 
End Property 
Public Property winkId As Guid 
    Get 
     Return _wkId 
    End Get 
    Set(ByVal value As Guid) 
     _wkId = value 
    End Set 
End Property 
Public Property datumVerdeling As DateTime 
    Get 
     Return _datumVerdeling 
    End Get 
    Set(ByVal value As DateTime) 
     _datumVerdeling = value 
    End Set 
End Property 
End Class 

而對於被完整的緣故，這是我收到的錯誤。

bij System.Data.Linq.SqlClient.SqlJoin.set_Left(SqlSource value) 
    bij System.Data.Linq.SqlClient.SqlMultiplexer.Visitor.VisitMultiset(SqlSubSelect sms) 
    bij System.Data.Linq.SqlClient.SqlVisitor.VisitSubSelect(SqlSubSelect ss) 
    bij System.Data.Linq.SqlClient.SqlVisitor.Visit(SqlNode node) 
    bij System.Data.Linq.SqlClient.SqlVisitor.VisitExpression(SqlExpression exp) 
    bij System.Data.Linq.SqlClient.SqlMultiplexer.Visitor.VisitSelect(SqlSelect select) 
    bij System.Data.Linq.SqlClient.SqlVisitor.Visit(SqlNode node) 
    bij System.Data.Linq.SqlClient.SqlProvider.BuildQuery(ResultShape resultShape, Type resultType, SqlNode node, ReadOnlyCollection`1 parentParameters, SqlNodeAnnotations annotations) 
    bij System.Data.Linq.SqlClient.SqlProvider.BuildQuery(Expression query, SqlNodeAnnotations annotations) 
    bij System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Compile(Expression query) 
    bij System.Data.Linq.CompiledQuery.ExecuteQuery(DataContext context, Object[] args) 
    bij System.Data.Linq.CompiledQuery.Invoke[TArg0,TArg1,TResult](TArg0 arg0, TArg1 arg1) 
    bij RackJobbing.UI.ucArtikelInfo.getLatestDate(Guid artikelId) in D:\EasySolutions\TFS\Provoost\Development\RackJobbing\RackJobbing.UI\Snelinvoer\Verdeling\ucArtikelInfo.vb:regel 69 
    bij RackJobbing.UI.ucArtikelInfo.UpdateInfo() in D:\EasySolutions\TFS\Provoost\Development\RackJobbing\RackJobbing.UI\Snelinvoer\Verdeling\ucArtikelInfo.vb:regel 111 
    bij RackJobbing.UI.frmPrePlanning.UcVerdeling1_ArtikelWinkelChanged() in D:\EasySolutions\TFS\Provoost\Development\RackJobbing\RackJobbing.UI\Snelinvoer\Verdeling\frmPrePlanning.vb:regel 280 
    bij RackJobbing.UI.ucVerdeling.grdVerdeling_EnterCell(Object sender, EventArgs e) in D:\EasySolutions\TFS\Provoost\Development\RackJobbing\RackJobbing.UI\Snelinvoer\Verdeling\ucVerdeling.vb:regel 339 
    bij C1.Win.C1FlexGrid.C1FlexGridBase.OnEnterCell(EventArgs e) 
    bij C1.Win.C1FlexGrid.C1FlexGridBase.a9() 
    bij C1.Win.C1FlexGrid.C1FlexGridBase.OnGridChanged(Object sender, GridChangedEventArgs e) 
    bij C1.Win.C1FlexGrid.C1FlexGrid.OnGridChanged(Object sender, GridChangedEventArgs e) 
    bij C1.Win.C1FlexGrid.t.bc(GridChangedTypeEnum A_0, Int32 A_1, Int32 A_2, Int32 A_3, Int32 A_4) 
    bij C1.Win.C1FlexGrid.t.bn(GridChangedTypeEnum A_0) 
    bij C1.Win.C1FlexGrid.p.n(C1FlexGridBase A_0, CellRange A_1, Boolean A_2) 
    bij C1.Win.C1FlexGrid.C1FlexGridBase.Select(CellRange rg, Boolean show) 
    bij C1.Win.C1FlexGrid.ab.o(MouseEventArgs A_0) 
    bij C1.Win.C1FlexGrid.ab.l(MouseEventArgs A_0) 
    bij C1.Win.C1FlexGrid.C1FlexGridBase.OnMouseDown(MouseEventArgs e) 
    bij System.Windows.Forms.Control.WmMouseDown(Message& m, MouseButtons button, Int32 clicks) 
    bij System.Windows.Forms.Control.WndProc(Message& m) 
    bij C1.Win.C1FlexGrid.Util.BaseControls.ScrollableControl.WndProc(Message& m) 
    bij System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) 
    bij System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) 
    bij System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) 
    bij System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) 
    bij System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) 
    bij System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) 
    bij System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) 
    bij System.Windows.Forms.Application.Run(ApplicationContext context) 
    bij Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun() 
    bij Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel() 
    bij Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine) 
    bij RackJobbing.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:regel 81 
    bij System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) 
    bij System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) 
    bij Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() 
    bij System.Threading.ThreadHelper.ThreadStart_Context(Object state) 
    bij System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) 
    bij System.Threading.ThreadHelper.ThreadStart() 

我會很感激在解決我的問題的任何幫助，因爲我真的似乎無法找到解決辦法:(

Answer 1

解決方案：

Public Shared CompiledLatestDate As Func(Of RackJobbingDataDataContext, ArtikelInfoParameters, IQueryable(Of VerdelingPlanning)) = _ 
    CompiledQuery.Compile(Function(db As RackJobbingDataDataContext, artInfo As ArtikelInfoParameters) _ 
     From verdplan As VerdelingPlanning In db.VerdelingPlannings _ 
       Join artPlan As ArtikelPlanning In db.ArtikelPlannings _ 
       On verdplan.VerdelingPlanningID Equals artPlan.VerdelingPlanningID _ 
       Join levDet As LeveringDetail In db.LeveringDetails _ 
       On artPlan.ArtikelPlanningID Equals levDet.ArtikelPlanningID _ 
       Join lev As Levering In db.Leverings _ 
       On levDet.LeveringID Equals lev.LeveringID _ 
       Where artPlan.ArtikelID.Equals(artInfo.artId) _ 
       And lev.WinkelID.Equals(artInfo.winkId) _ 
       And Not levDet.PlanningAantal.Equals(Nothing) _ 
       And levDet.PlanningAantal <> 0 _ 
       And verdplan.Datum < artInfo.datumVerdeling _ 
       Order By verdplan.Datum Descending _ 
      Select verdplan) 

解決了幾乎所有我的問題，即使我有時會得到一個NullReferenceException時，有收集（但並不總是給出錯誤的沒有價值，所以我還在研究那個）。

Answer 2

不同於SQL，ON子句的左，右兩側有不同範圍的知名度。

你需要把那名範圍的JOIN的ON子句的左側，在這之前是新的範圍從變量，變量右側JOIN的。

在這裏，我已經切換變量在ON子句中。

From verdplan As VerdelingPlanning In db.VerdelingPlannings _ 
    Join artPlan As ArtikelPlanning In db.ArtikelPlannings _ 
    On verdplan.VerdelingPlanningID Equals artPlan.VerdelingPlanningID _ 
    Join levDet As LeveringDetail In db.LeveringDetails _ 
    On artPlan.ArtikelPlanningID Equals levDet.ArtikelPlanningID _ 
    Join lev As Levering In db.Leverings _ 
    On levDet.LeveringID Equals lev.LeveringID _