VB.net Linq Join Ausdruck Fehler

Question

Public Class ListComparison 
    Public Function CompareTwoLists(Of T1, T2, TDuplicate As DuplicateExpression)(list1 As IEnumerable(Of T1), list2 As IEnumerable(Of T2), compareValue As Func(Of T1, T2, Boolean), DuplicateExpression As List(Of TDuplicate)) As Boolean 
     Return list1.[Select](Function(item1) list2.Any(Function(item2) compareValue(item1, item2))).All(Function(search) search) AndAlso list2.[Select](Function(item2) list1.Any(Function(item1) compareValue(item1, item2))).All(Function(search) search) 
    End Function 
    Public Function CompareLists(Of T1, TDuplicate As DuplicateExpression)(list1 As IEnumerable(Of T1), list2 As IEnumerable(Of T1), DuplicateExpression As List(Of TDuplicate)) As String 
     Dim InvalidDuplicateExpression As List(Of TDuplicate) = New ExtensionHelper().ValidateColumnInList(Of T1, TDuplicate)(DuplicateExpression) 
     Dim js As New System.Web.Script.Serialization.JavaScriptSerializer() 
     If InvalidDuplicateExpression.Count() <= 0 Then 
      Dim Fields As String() = DuplicateExpression.[Select](Function(x) x.ExpressionName).ToArray() 
      Dim JoinExp = list1.Join(list2, Fields) 
      Dim IsDuplicate As Boolean = True 
      IsDuplicate = CompareTwoLists(list1, list2, Function(listx1, listx2) JoinExp.Any(), DuplicateExpression) 
      If IsDuplicate Then 
       Return js.Serialize(New With { _ 
        Key .IsValidateExpression = True, _ 
        Key .IsValidateDuplicate = IsDuplicate, _ 
        Key .Message = "Duplicate Items in the List" _ 
       }) 
      Else 
       Return js.Serialize(New With { _ 
        Key .IsValidateExpression = True, _ 
        Key .IsValidateDuplicate = IsDuplicate _ 
       }) 
      End If 
     Else 
      Return js.Serialize(New With { _ 
       Key .IsValidateExpression = False, _ 
       Key .InvalidExpressions = InvalidDuplicateExpression, _ 
       Key .Message = "Duplicate Expression is not Invalid" _ 
      }) 
     End If 
    End Function   
    Public Shared Function CreateSelector(Of T)(PropertyNames As IEnumerable(Of String)) As Func(Of T, Object) 
     Dim SourceType = GetType(T) 
     Dim Parameter = Expression.Parameter(SourceType, "e") 
     Dim Properties = PropertyNames.[Select](Function(Name) Expression.PropertyOrField(Parameter, Name)).ToArray() 
     Dim Selector = Expression.Lambda(Of Func(Of T, Object))(Expression.[Call](GetType(Tuple), "Create", Properties.[Select](Function(p) p.Type).ToArray(), Properties), Parameter) 
     Return Selector.Compile() 
    End Function 
    Public Shared Function Join(Of T)(Left As IEnumerable(Of T), Right As IEnumerable(Of T), PropertyNames As IEnumerable(Of String)) As IEnumerable(Of Tuple(Of T, T)) 
     Dim KeySelector = CreateSelector(Of T)(PropertyNames) 
     Return Left.Join(Right, KeySelector, KeySelector, AddressOf Tuple.Create) 
    End Function 
End Class 

Wenn ich diesen Code kompiliere bekomme ich folgenden Fehler.

Fehler 15 Überladungsauflösung ist fehlgeschlagen, weil kein zugängliches 'Join' diese Anzahl von Argumenten akzeptiert.

Dim JoinExp = list1.Join(list2, Fields) 

Der Fehler ist auf dem oberen Zeile. Dies wird hauptsächlich für den Listenvergleich mit dynamischen Spalteneigenschaften verwendet. Dieser Code funktioniert ordnungsgemäß in C# .net. Wenn ich C# .net Code zu Vb.net umwandle; diesen Fehler bekommen. Wie löst man das in Vb.net?

Answer 1

Anscheinend ist der C# Join Funktion eine Erweiterungsmethode

public static IEnumerable<Tuple<T, T>> Join<T> (
    this IEnumerable<T> Left, 
    IEnumerable<T> Right, 
    IEnumerable<string> PropertyNames 
) 

In diesem Fall war müssen Sie add the <Extension> attribute, um es in VB.NET.