ByRef Local Variable using Linq - vb.net

Question

I'm having trouble with selecting only part of a collection and passing it by reference.
So I have a custom class EntityCollection which is , who guessed, a collection of entities. I have to send these entities over HTTPSOAP to a webservice.
Sadly my collection is really big, let's say 10000000 entities, which throws me an HTTP error telling me that my request contains too much data.
The method I am sending it to takes a Reference of the collection so it can further complete the missing information that is autogenerated upon creation of an entity.
My initial solution:
For i As Integer = 0 To ecCreate.Count - 1 Step batchsize
Dim batch As EntityCollection = ecCreate.ToList().GetRange(i, Math.Min(batchsize, ecCreate.Count - i)).ToEntityCollection()
Q.Log.Write(SysEnums.LogLevelEnum.LogInformation, "SYNC KLA", "Creating " & String.Join(", ", batch.Select(Of String)(Function(e) e("nr_inca")).ToArray()))
Client.CreateMultiple(batch)
Next
ecCreate being an EntityCollection.
What I forgot was that using ToList() and ToEntityCollection() (which I wrote) it creates a new instance...
At least ToEntityCollection() does, idk about LINQ's ToList()...
<Extension()>
Public Function ToEntityCollection(ByVal source As IEnumerable(Of Entity)) As EntityCollection
Dim ec As New EntityCollection()
'ec.EntityTypeName = source.FirstOrDefault.EntityTypeName
For Each Entity In source
ec.Add(Entity)
Next
Return ec
End Function
Now, I don't imagine my problem would be solved if I change ByVal to ByRef in ToEntityCollection(), does it?
So how would I actually pass just a part of the collection byref to that function?
Thanks
EDIT after comments:
#Tim Schmelter it is for a nightly sync operation, having multiple selects on the database is more time intensive then storing the full dataset.
#Craig Are you saying that if i just leave it as an IEnumerable it will actually work? After all i call ToArray() in the createmultiple batch anyway so that wouldn't be too much of a problem to leave out...
#NetMage you're right i forgot to put in a key part of the code, here it is:
Public Class EntityCollection
Implements IList(Of Entity)
'...
Public Sub Add(item As Entity) Implements ICollection(Of Entity).Add
If IsNothing(EntityTypeName) Then
EntityTypeName = item.EntityTypeName
End If
If EntityTypeName IsNot Nothing AndAlso item.EntityTypeName IsNot Nothing AndAlso item.EntityTypeName <> EntityTypeName Then
Throw New Exception("EntityCollection can only be of one type!")
End If
Me.intList.Add(item)
End Sub
I Think that also explains the List thing... (BTW vb or c# don't matter i can do both :p)
BUT: You got me thinking properly:
Public Sub CreateMultiple(ByRef EntityCollection As EntityCollection)
'... do stuff to EC
Try
Dim ar = EntityCollection.ToArray()
Binding.CreateMultiple(ar) 'is also byref(webservice code)
EntityCollection.Collection = ar 'reset property, see below
Catch ex As SoapException
Raise(GetCurrentMethod(), ex)
End Try
End Sub
And the evil part( at least i think it is) :
Friend Property Collection As Object
Get
Return Me.intList
End Get
Set(value As Object)
Me.Clear()
For Each e As Object In value
Me.Add(New Entity(e))
Next
End Set
End Property
Now, i would still think this would work, since in my test if i don't use Linq or ToEntityCollection the byref stuff works perfectly fine. It is just when i do the batch thing, then it doesn't... I was guessing it could maybe have to do with me storing it in a local variable?
Thanks already for your time!
Anton

Answer 1

The problem was that i was replacing the references of Entity in my local batch, instead of in my big collection... I solved it by replacing the part of the collection that i sent as a batch with the batch itself, since ToList() and ToEntityCollection both create a new object with the same reference values...
Thanks for putting me in the correct direction guys!