I have setup a remote Business Object that uses wcf to iis to update. I also have a separate service to iis under the same domain that is setup for a callback. The callback fires fine, but when I try doing a refresh of the business object, I get the following error. I'm not sure what it means. Any ideas?
There was an error while trying to serialize parameter http://ws.lhotka.net/WcfDataPortal:FetchResult. The InnerException message was 'Enum value '0' is invalid for type 'System.Security.Permissions.SecurityAction' and cannot be serialized. Ensure that the necessary enum values are present and are marked with EnumMemberAttribute attribute if the type has DataContractAttribute attribute.'. Please see InnerException for more details.
What are you trying to pass through your callback? A CSLA business object? Or FetchResult, which would contain a business object?
You can't do that without digging relatively deep into WCF. The WCF data portal channel may not look overly complex, but it does use a couple deep extensibility features of WCF to ensure that the correct serialization engine is used. If you don't do that, the default engine is used (DataContractSerializer) and it simply can't handle the kinds of object graphs used in a typical business model.
I'm passing a simple string in the callback. I noticed another thread having a similar problem.
http://forums.lhotka.net/forums/thread/14905.aspx
A little more info, here is the interface of my callback
namespace
Company.Helpdesk.Library.Wcf { //The interface the serice exposes[
ServiceContract(Name = "WcfTicketService",Namespace =
"http://localhost/HelpDesk/services/WcfTicketService/",SessionMode =
SessionMode.Required,CallbackContract =
typeof(ITicketChangedCallback))] public interface ITicketChangedPub {[
OperationContract(IsInitiating = true)] void Subscribe(string id);[
OperationContract(IsTerminating = true)] void Unsubscribe(string id);[
OperationContract(IsOneWay=false)] int Count();}
}
namespace
Company.Helpdesk.Library.Wcf { //The interface that clients must implement public interface ITicketChangedCallback {[
OperationContract(IsOneWay = true)] void TicketChanged(string id);}
}
I haven't done any callbacks, so I'm not going to be much help troubleshooting the specifics.
However, can you confirm that your DataPortal_XYZ code is running on the server before the failure? In other words, can you find out if the exception is occurring on the way to the server, or after execution is already there?
I should have given these details up front.
I have a BusinessList object with a static method called GetUserActiveTicketList.
This businesslist object also implements the WcfTicketServiceCallback interface from the above post.
In the GetUserActiveTicketList method I fill a criteria object and call the dataportal fetch method. Once the dataportal fetch has completed, I then hookup the callback to the other wcf service. Right now, for testing purposes, this callback webservice has a timer that fires the callback after 1 minute. When the callback fires, I have the businesslist close the callback client, and fire an event. The client application then calls the GetUserActiveTicketList again. This is where it errors out. If I call the GetUserActiveTicketList again, before the callback fires, it works fine.
It is important to realize that the data portal is not designed
with callbacks in mind. I would be VERY suspicious of anything that calls back
to the client-side instance of a business object, because that object should be
considered obsolete as soon as the data portal has been called.
Remember that the data portal clones the object across the wire,
and then the server-side object is cloned back to the client and that new
instance MUST replace the old instance on the client.
If you do a callback, you’d be calling back to the
effectively dead and obsolete original object, which seems pointless, as that
object should have been, or should be, discarded.
Rocky
From: Curelom
[mailto:cslanet@lhotka.net]
Sent: Wednesday, May 23, 2007 9:52 AM
To: rocky@lhotka.net
Subject: Re: [CSLA .NET] wcf - callbacks
I should have given these details up front.
I have a BusinessList object with a static method called
GetUserActiveTicketList.
This businesslist object also implements the WcfTicketServiceCallback
interface from the above post.
In the GetUserActiveTicketList method I fill a criteria object and call
the dataportal fetch method. Once the dataportal fetch has completed, I
then hookup the callback to the other wcf service. Right now, for testing
purposes, this callback webservice has a timer that fires the callback
after 1 minute. When the callback fires, I have the businesslist close
the callback client, and fire an event. The client application then calls
the GetUserActiveTicketList again. This is where it errors out. If
I call the GetUserActiveTicketList again, before the callback fires, it works
fine.
Here is the code I am calling. I am not putting the callback on the old list, but the newly created one.
public static TicketList GetUserActiveTicketList(string user) { if (!CanGetObject()) throw new System.Security.SecurityException("User not authorized to view a TicketList"); TicketCriteria crit = new TicketCriteria(TicketQueryType.AssignedToStatus, "Open", user); TicketList tl = DataPortal.Fetch<TicketList>(crit);tl.hookupProxy();
return tl;}
[
NonSerialized()][
NotUndoable()] private WcfTicketServiceClient wcfClient; public void hookupProxy() { InstanceContext callback;callback = new InstanceContext(this);
wcfClient =
new WcfTicketServiceClient(callback);wcfClient.Subscribe(
this._dependencyId); return;}
Curelom:
There was an error while trying to serialize parameter http://ws.lhotka.net/WcfDataPortal:FetchResult. The InnerException message was 'Enum value '0' is invalid for type 'System.Security.Permissions.SecurityAction' and cannot be serialized. Ensure that the necessary enum values are present and are marked with EnumMemberAttribute attribute if the type has DataContractAttribute attribute.'. Please see InnerException for more details.
OK, I have isolated this issue. It appears to be a bug in the NetDataContractSerializer (the WCF replacement for the BinaryFormatter). As such, it is not at all clear to me that there's a fix or workaround short of Microsoft addressing the problem.
http://www.lhotka.net/weblog/WCFNetDataContractSerializerAndSecurityException.aspx
I haven't quite given up on a workaround yet, but it is hard to see any good solution I can provide...
Copyright (c) Marimer LLC