LINQ Query returning Ienumerable - vb.net

Question

I have the following 2 classes
Public Class LookupsModel
Implements IEnumerable(Of LookupModel)
Public _LookupModel() As LookupModel
Public Sub New(pArray As ArrayList)
_LookupModel = New LookupModel(pArray.Count - 1) {}
Dim i As Integer
For Each l As LookupModel In pArray
_LookupModel(i) = l
i += 1
Next
End Sub
Public Function GetEnumerator() As IEnumerator(Of LookupModel) Implements IEnumerable(Of LookupModel).GetEnumerator
Return New LookupEmum(_LookupModel)
End Function
Public Function GetEnumerator1() As IEnumerator Implements IEnumerable.GetEnumerator
Return New LookupEmum(_LookupModel)
End Function
Public Property Heading1 As String
Public Property Heading2 As String
Public Property Heading3 As String
Public Property Heading4 As String
Public Property Heading5 As String
Public Property Heading6 As String
Public Property CalledBy As String
Public Property ParmName1 As String
Public Property ParmName2 As String
Public Property ParmName3 As String
Public Property ParmName4 As String
Public Property ParmName5 As String
Public Property ParmName6 As String
Public Property ValueFieldGetter() As Func(Of LookupModel, String)
Public Property DescriptionFieldGetter() As Func(Of LookupModel, String)
End Class
Public Class LookupModel
Public Sub New(ByVal Key As String, Optional ByVal Desc As String = Nothing, Optional Extra_1 As String = Nothing, Optional Extra_2 As String = Nothing, Optional Extra_3 As String = Nothing, Optional Extra_4 As String = Nothing)
Me.Field1 = Key
Me.Field2 = Desc
Me.Field3 = Extra_1
Me.Field4 = Extra_2
Me.Field5 = Extra_3
Me.Field6 = Extra_4
End Sub
Public Sub New()
Me.Field1 = Nothing
Me.Field2 = Nothing
Me.Field3 = Nothing
Me.Field4 = Nothing
Me.Field5 = Nothing
Me.Field6 = Nothing
End Sub
Public Property Field1 As String
Public Property Field2 As String
Public Property Field3 As String
Public Property Field4 As String
Public Property Field5 As String
Public Property Field6 As String
End Class
This is the linq query:
Dim lm As LookupsModel = GetLookupsModel(FieldID, lookup, LookupPage:=1, SearchField:=SearchField, SearchFields:=searchFields, SearchString:=String.Empty)
Dim lm2 As IEnumerable(Of LookupModel) = lm.Where(Function(p) p.Field1.Contains("A"))
I'm trying to query LookupsModel and only get the LookupModel collection where LookupModel.Field1 starts with "A". But the following query returns an Ienumerable of LookupModel, not the LookupsModel object with those items excluded. How do we accomplish this and get a LookupsModel object as a result?

Answer 1

You can't directly cast from an IEnumerable(Of LookpupModel) to a LookupsModel. You have a few options:
Add a constructor that takes an existing IEnumerable(Of LookupModel)
Convert the output of Where to an ArrayList and use your existing constructor.
But what's the point of LookupsModel in the first place? All you're doing is wrapping an array of LookupModel and not adding any additional functionality. Why not just stick with IEnumerable(Of LookupModel)?