Problem with serialization of objects that raise events handled by a non-serializable object (like a Windows Form)

PStanev posted on Monday, August 04, 2008

Problem with serialization of objects that raise events handled by a non-serializable object (like a Windows Form)

I have problem: (serializing objects that raise events when those events are handled by a non-serializable object (like a Windows Form). )The only diffence in my code is thet I dont use the standard EventHandler Because I have input parameteres. Here is my code:

<NonSerialized()> _

Private mNonSerializableSM As SMHandler

Private mSerializableSM As SMHandler

Delegate Sub SMHandler(ByVal Message As String, ByVal MessageType As MsgBoxStyle)

Public Custom Event SimpleMessageEvent As SMHandler

AddHandler(ByVal value As SMHandler)

If value.Target.GetType.IsSerializable Then

mSerializableSM = CType([Delegate].Combine(mSerializableSM, value), SMHandler)

Else

mNonSerializableSM = CType([Delegate].Combine(mNonSerializableSM, value), SMHandler)

End If

End AddHandler

RemoveHandler(ByVal value As SMHandler)

If value.Target.GetType.IsSerializable Then

mSerializableSM = CType([Delegate].Remove(mSerializableSM, value), SMHandler)

Else

mNonSerializableSM = CType([Delegate].Remove(mNonSerializableSM, value), SMHandler)

End If

End RemoveHandler

RaiseEvent(ByVal Message As String, ByVal MessageType As MsgBoxStyle)

If mNonSerializableSM IsNot Nothing Then mNonSerializableSM(Message, MessageType)

If mSerializableSM IsNot Nothing Then mSerializableSM(Message, MessageType)

End RaiseEvent

End Event

Everithing look right , but I still get the runtime error.

Please Help.

Thank You.

tetranz replied on Monday, August 04, 2008

I don't know why your code is not working but, just as a suggestion, the way I usually do this sort of thing is to use databinding, i.e, use the PropertyChanged event. It is already written and well debugged in CSLA. Databinding is the "official" way of communicating between an object and a form.

If you need to pass more information than just the fact that a property has changed then you can read other properties of your object in the event handler.

Ross

stefan replied on Tuesday, August 05, 2008

Hi,

I once solved this problem by implementing my own NonSerialized event inside my BO the following way (sorry, C# Smile [:)]

):

#region OnCriteriaEndEdit

        // A custom event to notify UI controls when EndEdit (=>AcceptChangesComplete) is called!
        [NonSerialized, NotUndoable]
        private EventHandler _onCriteriaEndEdit;

        public event EventHandler OnCriteriaEndEdit
        {
            [System.Runtime.CompilerServices.MethodImpl(
                System.Runtime.CompilerServices.MethodImplOptions.Synchronized)]
            add
            {
                _onCriteriaEndEdit = (EventHandler)Delegate.Combine(_onCriteriaEndEdit, value);
            }
            [System.Runtime.CompilerServices.MethodImpl(
                System.Runtime.CompilerServices.MethodImplOptions.Synchronized)]
            remove
            {
                _onCriteriaEndEdit = (EventHandler)Delegate.Remove(_onCriteriaEndEdit, value);
            }
        }

        protected override void AcceptChangesComplete()
        {
            base.AcceptChangesComplete();
            if (_onCriteriaEndEdit != null)
                _onCriteriaEndEdit (this, EventArgs.Empty);
        }

#endregion // OnCriteriaEndEdit

Stefan

dg78 replied on Sunday, October 12, 2008

Hi Rocky,

I have the same problem in vb.net.

I found this post in your blog : http://www.lhotka.net/weblog/BetterVersionOfTheNET20EventserializationSolution.aspx

I code as you (or I think I do). In fact, I took the same code as event code in CSLA 3.5 (PropertyChanged / PropertyChanging / Saved ..).

Here my code in ucCustomer (user control in UI) and in Customer (in BLL).

-) in ucCustomer

Private Sub myevent(ByVal sender As Object, ByVal e As EVZoneEventArgs) Handles mCustomer.ErreurValideZone

MessageBox.Show(e.StrErreur)

End Sub

-) in Customer

<NonSerialized()> _

Public _nonSerializableEVZHandlers As EventHandler(Of EVZoneEventArgs)

Public _SerializableEVZHandlers As EventHandler(Of EVZoneEventArgs)

Public Custom Event ErreurValideZone As EventHandler(Of EVZoneEventArgs)

AddHandler(ByVal value As EventHandler(Of EVZoneEventArgs))

If value.Method.IsPublic AndAlso (value.Method.DeclaringType.IsSerializable OrElse value.Method.IsStatic) Then

_SerializableEVZHandlers = CType([Delegate].Combine(_SerializableEVZHandlers, value), EventHandler(Of EVZoneEventArgs))

Else

_nonSerializableEVZHandlers = CType([Delegate].Combine(_nonSerializableEVZHandlers, value), EventHandler(Of EVZoneEventArgs))

End If

End AddHandler

RemoveHandler(ByVal value As EventHandler(Of EVZoneEventArgs))

If value.Method.IsPublic AndAlso (value.Method.DeclaringType.IsSerializable OrElse value.Method.IsStatic) Then

_SerializableEVZHandlers = CType([Delegate].Remove(_SerializableEVZHandlers, value), EventHandler(Of EVZoneEventArgs))

Else

_nonSerializableEVZHandlers = CType([Delegate].Remove(_nonSerializableEVZHandlers, value), EventHandler(Of EVZoneEventArgs))

End If

End RemoveHandler

RaiseEvent(ByVal sender As System.Object, ByVal e As EVZoneEventArgs)

If Not _SerializableEVZHandlers Is Nothing Then

_SerializableEVZHandlers(sender, e) '.Invoke(sender, e)

End If

If Not _nonSerializableEVZHandlers Is Nothing Then

_nonSerializableEVZHandlers(sender, e) '.Invoke(sender, e)

End If

End RaiseEvent

End Event

Public Class EVZoneEventArgs : Inherits EventArgs

Private mNumErreur As Integer

Private mStrErreur As String

Public Sub New(ByVal numErreur As Integer, ByVal strErreur As String)

mNumErreur = numErreur

mStrErreur = strErreur

End Sub

Public ReadOnly Property NumErreur() As Integer

Get

Return mNumErreur

End Get

End Property

Public ReadOnly Property StrErreur() As String

Get

Return mStrErreur

End Get

End Property

End Class

The issue during the run time appends in CSLA in BinaryFormatterWrapper.vb :

Public Sub Serialize(ByVal serializationStream As System.IO.Stream, ByVal graph As Object) _

Implements ISerializationFormatter.Serialize

_formatter.Serialize(serializationStream, graph)

End Sub

To test, I put breakpoints and I go step by step.

I saw that _nonSerializableEVZHandlers is used.

If I put a comment before _formatter.Serialize(serializationStream, graph) then the UI consume the event but .. it is not good because I change CSLA and there is no serialization.

If I put a comment in the event code in the UI and no comment before _formatter.Serialize, I have no runtime error

I don't understand where is my mistake.

Thanks for your help.

Dominique

PS: to Ross (tetranz) : I think that databinding is "a" way of communicating between an object and a form. But it is not the only way, sometimes it is useful to use an event.

To Stefan : I am sorry but I don't use C# Smile [:)]

dg78 replied on Tuesday, December 09, 2008

*bump*

I reactivate this thread because I didn't have an answer.

During this time, I put a comment before _formatter.Serialize(serializationStream, graph) in Csla (BinaryFormaterHelper.vb) but it is not a solution.

I use now Csla vb 3.52 and I have always the same problem.

I use in a BO class, the same code there is in Bindable.vb.

I can see (with breakpoints and step by step) that_nonSerializableEVZHandlers is used for the AddHandler to define the event.

The problem is in _formatter.Serialize(serializationStream, graph) if graph include _nonSerializableEVZHandlers. It want serialize the user control.

I test without _nonSerializableEVZHandlers and it is good.

Thanks for help.

dg78 replied on Tuesday, December 09, 2008

I think that I found the solution :

If I add in my code : <NotUndoable()> _ it is OK :

<NonSerialized()> _

<NotUndoable()> _

Public _nonSerializableEVZHandlers As EventHandler(Of EVZoneEventArgs)

<NotUndoable()> _

Public _SerializableEVZHandlers As EventHandler(Of EVZoneEventArgs)

Rocky, you use this code in 4 places in Csla.

Two with <NotUndoable()> _ : BusinessBase.vb and BusinessListBase

Two without <NotUndoable()> _ : Bindable.vb and ExtendedBindingList.vb

Is it normal ?