Serialize a collection of objects

[nemaroller]

I'm trying to serialize a collection of a certain type of class...

I keep getting a Reflection error when I attempt to serialize with the code below... with the two classes below. I can sucessfully serialze the SalesRep class, but not its collection class... I CAN SUCESSFULLY serialize it to a BinaryFormatter ...and retrieve.. but not when using XMLSerializer...

Dim gwhiz As Xml.Serialization.XmlSerializer = New Xml.Serialization.XmlSerializer(GetType(SalesRepCollection))
        Dim rep1 As SalesRep = New SalesRep(12, "John", "Labrizzi")
        Dim rep2 As SalesRep = New SalesRep(5, "Eddie", "Gasser")
        Dim myReps As SalesRepCollection = New SalesRepCollection()
        myReps.Add(rep1)
        myReps.Add(rep2)
 
       dim fs as System.IO.FileStream = New System.IO.FileStream("C:\sales.xml", IO.FileMode.Create)
        gwhiz.Serialize(fs, myReps)
        fs.Close()

Here is the SalesRep Class:

<Serializable()> Public Class SalesRep
 
    Public Sub New()
 
    End Sub
 
    Public Sub New(ByVal RepID As Int32, ByVal RepFirstName As String, _
    ByVal RepLastName As String, Optional ByVal RepMiddleName As String = Nothing)
 
        sRepID = RepID
        sRepFName = RepFirstName
        sRepMName = RepMiddleName
        sRepLName = RepLastName
    End Sub
 
    Private sRepID As Int32
    Private sRepFName As String
    Private sRepMName As String
    Private sRepLName As String
 
    Public Property SalesRepId() As Int32
        Get
            Return sRepID
        End Get
        Set(ByVal Value As Int32)
            sRepID = Value
        End Set
    End Property
    Public Property FirstName() As String
        Get
            Return sRepFName
        End Get
        Set(ByVal Value As String)
            sRepFName = Value
        End Set
    End Property
    Public Property MiddleName() As String
        Get
            Return sRepMName
        End Get
        Set(ByVal Value As String)
            sRepMName = Value
        End Set
    End Property
    Public Property LastName() As String
        Get
            Return sRepLName
        End Get
        Set(ByVal Value As String)
            sRepLName = Value
        End Set
    End Property

Here's the SalesRep collection class:

Option Strict Off
<Serializable()> Public Class SalesRepCollection
    Inherits System.Collections.CollectionBase
 
 
    Public Function Add(ByVal Salesman As SalesRep) As Integer
        ' Invokes Add method of the List object to add a object.
        Return List.Add(Salesman)
 
    End Function
    Public Sub New()
 
    End Sub
 
    Public Sub Remove(ByVal index As Integer)
 
        If index > Count - 1 Or index < 0 Then
 
        Else
            ' Invokes the RemoveAt method of the List object.
            List.RemoveAt(index)
        End If
    End Sub
 
    ' 
    Public Function GetItem(ByVal index As Integer) As SalesRep
        Return CType(List.Item(index), SalesRep)
    End Function
 
    
    Public Sub SetItem(ByVal index As Integer, ByVal SalesMan As SalesRep)
 
        List.Item(index) = CType(SalesMan, SalesRep)
    End Sub

[Edneeis]

See if these help:
http://www.dotnet247.com/247referenc.../16/80980.aspx

http://www.dotnet247.com/247referenc...26/133606.aspx

[Edneeis]

If you get the innerException for the reflection error you find that it is because you have not exposed a default accessor in the collection. Instead of using your get/set methods try adding this item property and everything should work then.

Default Public Property Item(ByVal index As Integer) As SalesRep
        Get
            Return CType(List.Item(index), SalesRep)
        End Get
        Set(ByVal Value As SalesRep)
            list.Item(index) = Value
        End Set
    End Property

[nemaroller]

You're correct, I had not declared a default public property...

And of course, it works now....

And equally of course, I am grateful.... you are not just the man, you are the GOD!

[nemaroller]

Here's a stumper....

The salesman class and collection class represented above are part of a bigger project....

The top level is actually a collection of invoices...
Each invoice has a customer, salesrep, date, etc

HERE'S THE TRICKY PART:

Each invoice has a collection of invoice items (chair, sofa, etc)


Now, I had made an InvoiceItem Class which holds the properties of a single item... for example, Chair would include the styleID, manufacturer ID, width, length, height....

To hold a collection of those InvoiceITems... I made an InvoiceItemCollection class....

What I want to be able to do is STICK that collection of InvoiceITems into the Invoice class...

something like Dim InvoiceItems() As InvoiceItemCollection

So that when I save the collection of Invoices (InvoiceCollection), I am actually saving each invoice, and each invoice item inside each invoice element....

<InvoiceCollection>
   <Invoice>
      <DateofSale>
      <SalesRep>
         <Fname>]
          <Lname>
      <Customer>
          <Fname>
           <Lname>
     <InvoiceItem>
               <Name>
               <ManufacturerID>
               <Length>
               <Width>
      </InvoiceItem>
      <InvoiceItem>
               <Name>
               <ManufacturerID>
               <Length>
               <Width>
      </InvoiceItem>
    </Invoice>
   <Invoice>
      .........'repeat for another invoice
   </Invoice>
</InvoiceCollection>

So you see, its a collection of a collection...
and I don't know if I should make Invoice inherit a collectionbase to hold the invoiceItems (which I couldn't get to work well), or simply Dim someVariable() As InvoiceCollection() , which did work when saving to file.... and since it worked saving to file... it has something to do with the default property setting...

[Edneeis]

Did you get the second thing to work or no?

Actually it seems you should have two collectio types: InvoiceCollection and InvoiceItemCollection.

InvoiceCollection holds a group of Invoices
Each Invoice object has an InvoiceItemCollection which holds a group of InvoiceItem objects.

[nemaroller]

Yes, I got everything to work... it makes great XML.... only problem now is trying to imbed a collection within a collection... (invoiceitems within invoices)....

I do have these classes:

InvoiceCollection
Invoice
InvoiceItemCollection
InvoiceItem

As of right now, I'm just using

Private invItemCollection As InvoiceItemCollection = New InvoiceItemCollection()

within the Invoice class....

problem is... it doesn't write the invoiceitemcollection to XML...

Imports DinesenClientLibrary.InvoiceItem
Imports DinesenClientLibrary.Customer
Imports DinesenClientLibrary.SalesRep
Imports DinesenClientLibrary.InvoiceItemCollection
 
<Serializable()> Public Class Invoice
    Private invID As Int32
    Private invNo As Int32
    Private invDate As Date
    Private sClass As Int32  'sales class special order, stock,etc
    Private InvCust As Customer
    Private InvItems As InvoiceItemCollection = New InvoiceItemCollection()
    Private sRep As SalesRep
    Private ClearedPO As Boolean 'ready for PO, authorized by eddie
 
    Public Sub New()
 
    End Sub
 
    Public Sub New(ByVal InvoiceCustomer As Customer, ByVal invoiceDate As Date, ByVal invoiceItems As InvoiceItemCollection, ByVal salesRep As SalesRep)
        InvItems = invoiceItems
        invDate = invoiceDate
        InvCust = InvoiceCustomer
        sRep = salesRep
 
    End Sub
 
   Public ReadOnly Property Item(ByVal a As Int32) As InvoiceItem
        Get
            Return CType(InvItems.GetItem(a), InvoiceItem)
        End Get
    End Property

[Edneeis]

Either it needs an XMLArray attribute for that property or its because you are exposing it as an item property of a non-collection. If its the latter try changing it to this:

Public ReadOnly Property InvoiceItems() As InvoiceItemCollection
        Get
            Return InvItems
        End Get
    End Property

Or it might need both, not sure.

And if you don't want to allow the user to add items then you can handle that in the InvoiceItemsCollection itself.

[nemaroller]

I will get around to responding to this... I just don't have that source code with me right now...

[nemaroller]

Thanks Edneesis... took a look at it this morning, took about five minutes to implement... and it works...

The namespace argument of the XMLArrray attribute makes little sense to me... but i guess it doesn't matter..