Using a WCF method that accepts an interface object

I have a WCF service that exposes a generic method in which one of the
parameters is an interface object (IObject - custom interface) and the
service starts up just fine but when an object that inherits from IObject is
passed, I get the following error:

"System.ServiceModel.CommunicationException: There was an error while trying
to serialize parameter http://tempuri.org/bj. The InnerException message
was 'Type 'WCFSharedLib.TestObject' with data contract name
'TestObject:http://schemas.datacontract.org/2004/07/WCFSharedLib' is not
expected. Add any types not known statically to the list of known types - for
example, by using the KnownTypeAttribute attribute or by adding them to the
list of known types passed to DataContractSerializer.'. Please see
InnerException for more details. --->
System.Runtime.Serialization.SerializationException: Type
'WCFSharedLib.TestObject' with data contract name
'TestObject:http://schemas.datacontract.org/2004/07/WCFSharedLib' is not
expected. Add any types not known statically to the list of known types - for
example, by using the KnownTypeAttribute attribute or by adding them to the
list of known types passed to DataContractSerializer.\r\n at
System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeAndVerifyTyp
e(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj,
Boolean verifyKnownType)\r\n at
System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithXsiTypeAtTopLevel(DataContract
dataContract, XmlWriterDelegator xmlWriter, Object obj)\r\n at
System.Runtime.Serialization.DataContractSerializer.InternalWriteObjectContent(XmlWriterDelegator
writer, Object graph)\r\n at
System.Runtime.Serialization.DataContractSerializer.InternalWriteObject(XmlWriterDelegator
writer, Object graph)\r\n at
System.Runtime.Serialization.XmlObjectSerializer.WriteObjectHandleExceptions(XmlWriterDelegator
writer, Object graph)\r\n at
System.Runtime.Serialization.XmlObjectSerializer.WriteObject(XmlDictionaryWriter
writer, Object graph)\r\n at
System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeParameterPart(XmlDictionaryWriter
writer, PartInfo part, Object graph)\r\n --- End of inner exception stack
trace ---\r\n\r\nServer stack trace: \r\n at System.ServiceModel.Di
spatcher.DataContractSerializerOperationFormatter.SerializeParameterPart(XmlDictionaryWriter
writer, PartInfo part, Object graph)\r\n at
System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeParameter(XmlDictionaryWriter
writer, PartInfo part, Object graph)\r\n at
System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeParameters(XmlDictionaryWriter
writer, PartInfo[] parts, Object[] parameters)\r\n at
System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeBody(XmlDictionaryWriter
writer, MessageVersion version, String action, MessageDescription
messageDescription, Object returnValue, Object[] parameters, Boolean
isRequest)\r\n at
System.ServiceModel.Dispatcher.OperationFormatter.SerializeBodyContents(XmlDictionaryWriter
writer, MessageVersion version, Object[] parameters, Object returnValue,
Boolean isRequest)\r\n at
System.ServiceModel.Dispatcher.OperationFormatter.OperationFormatterMessage.OperationFormatterBodyWriter.On
WriteBodyContents(XmlDictionaryWriter writer)\r\n at
System.ServiceModel.Channels.BodyWriter.WriteBodyContents(XmlDictionaryWriter
writer)\r\n at
System.ServiceModel.Channels.BodyWriterMessage.OnWriteBodyContents(XmlDictionaryWriter
writer)\r\n at
System.ServiceModel.Channels.Message.WriteBodyContents(XmlDictionaryWriter
writer)\r\n at
System.ServiceModel.Security.SecurityAppliedMessage.WriteBodyToSignThenEncryptWithFragments(Stream
stream, Boolean includeComments, String[] inclusivePrefixes, EncryptedData
encryptedData, SymmetricAlgorithm algorithm, XmlDictionaryWriter writer)\r\n
at
System.ServiceModel.Security.WSSecurityOneDotZeroSendSecurityHeader.ApplyBodySecurity(XmlDictionaryWriter
writer, IPrefixGenerator prefixGenerator)\r\n at
System.ServiceModel.Security.SecurityAppliedMessage.OnWriteMessage(XmlDictionaryWriter
writer)\r\n at
System.ServiceModel.Channels.Message.WriteMessage(XmlDictionaryWriter
writer)\r\n at
System.ServiceModel.Channels.BufferedMessageWriter.WriteMessage(Message mes
sage, BufferManager bufferManager, Int32 initialOffset, Int32
maxSizeQuota)\r\n at
System.ServiceModel.Channels.TextMessageEncoderFactory.TextMessageEncoder.WriteMessage(Message
message, Int32 maxMessageSize, BufferManager bufferManager, Int32
messageOffset)\r\n at
System.ServiceModel.Channels.MessageEncoder.WriteMessage(Message message,
Int32 maxMessageSize, BufferManager bufferManager)\r\n at
System.ServiceModel.Channels.HttpOutput.SerializeBufferedMessage(Message
message)\r\n at System.ServiceModel.Channels.HttpOutput.Send(TimeSpan
timeout)\r\n at
System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.SendRequest(Message
message, TimeSpan timeout)\r\n at
System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan
timeout)\r\n at
System.ServiceModel.Channels.ClientReliableChannelBinder`1.RequestClientReliableChannelBinder`1.OnRequest(TRequestChannel
channel, Message message, TimeSpan timeout, MaskingMode maskingMode)\r\n at
System.ServiceModel.
Channels.ClientReliableChannelBinder`1.Request(Message message, TimeSpan
timeout, MaskingMode maskingMode)\r\n at
System.ServiceModel.Channels.ClientReliableChannelBinder`1.Request(Message
message, TimeSpan timeout)\r\n at
System.ServiceModel.Security.SecuritySessionClientSettings`1.SecurityRequestSessionChannel.Request(Message
message, TimeSpan timeout)\r\n at
System.ServiceModel.Dispatcher.RequestChannelBinder.Request(Message message,
TimeSpan timeout)\r\n at
System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean
oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs,
TimeSpan timeout)\r\n at
System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean
oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs)\r\n
at
System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage
methodCall, ProxyOperationRuntime operation)\r\n at
System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage
message)\r\n\r\nException reth
rown at [0]: \r\n at
System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage
reqMsg, IMessage retMsg)\r\n at
System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData,
Int32 type)\r\n at ISomeContract.Blah(Object obj)\r\n at
SomeContractClient.Blah(Object obj) in
C:\\Projects\\Junk\\WCFInterfaceTest\\WCFSharedLib\\WCFProxy.cs:line 106\r\n
at WCFInterfaceTest.Form1.button1_Click(Object sender, EventArgs e) in
C:\\Projects\\Junk\\WCFInterfaceTest\\WCFInterfaceTest\\Form1.cs:line 28"

Here is my Interface definition:

using System;
using System.Collections.Generic;
using System.Text;

namespace WCFSharedLib
{
public interface IObject
{
string Name { get;set;}
}
}

Here is the TestObject that inherits from IObject and it is also the object
I'm passing to the WCF method:
using System;
using System.Collections.Generic;
using System.Text;
using System.ServiceModel;
using System.Runtime.Serialization;

namespace WCFSharedLib
{
[DataContract]
public class TestObject:IObject, IExtensibleDataObject
{
private string _name;
#region IObject Members

[DataMember]
public string Name
{
get
{
return _name;
}
set
{
_name = value;
}
}

#endregion

private ExtensionDataObject extensionDatavalue;

#region IExtensibleDataObject Members

public ExtensionDataObject ExtensionData
{
get
{
return extensionDatavalue;
}
set
{
extensionDatavalue = value;
}
}

#endregion
}
}

Here is the proxy client:
using System;
using System.Collections.Generic;
using System.Text;

namespace WCFSharedLib
{
public class WCFProxy: System.ServiceModel.ClientBase<ISomeContract>,
ISomeContract
{
public WCFProxy()
{

}
public WCFProxy(string
endpointConfigurationName):base(endpointConfigurationName)
{
}

public WCFProxy(string endpointConfigurationName, string
remoteAddress)
: base(endpointConfigurationName, remoteAddress)
{
}

public WCFProxy(string endpointConfigurationName,
System.ServiceModel.EndpointAddress remoteAddress)
: base(endpointConfigurationName, remoteAddress)
{
}

public WCFProxy(System.ServiceModel.Channels.Binding binding,
System.ServiceModel.EndpointAddress remoteAddress)
: base(binding, remoteAddress)
{

}

#region ISomeContract Members

public object Blah(object obj)
{
return base.Channel.Blah(obj);
}

#endregion
}
}

And finally the method on the service that needs to be called:

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.Serialization;

namespace WCFHostingApp
{
public class SomeContract:ISomeContract
{
#region ISomeContract Members

public object Blah(object obj)
{
WCFSharedLib.IObject temp = obj as WCFSharedLib.IObject;
if (temp != null)
{
temp.Name = "Return Value: " + temp.Name;
}
return obj;
}

#endregion
}
}

Anyone have any ideas??

It is because the interfaces are not objects and in fact, they can not be
serialized.

I recommend to you, that use a serializable class derived from your
interface, marking all their members as virtual or insert a base code if
required. Then send the information by using the class in the services
methods.

When you obtain the info use the shared class and cast to the interface if
necessary. Use the KnownTypeAttribute and ServiceKnownAttribute to mark as
known the class.

Regards,

--
Ronald Ramirez Moran (aka DlanorOk)
Personal Space: http://dlanorok.spaces.live.com
Blog: http://ecuador.latindevelopers.net/blogs/dlanorok
--

"Matthew Yost" <Matthew Yost@xxxxxx> wrote in message
news:28E7CB75-90D5-4FE4-BAF7-0C1D8B10D9FC@xxxxxx

I tried changing creating the base class that inherits from the interface
IObject and I'm recieving the same exception each time. It's asking for
known types. I've decorated the ISomeContract with the
ServiceKnownType(typeof(DBObject))] attribute but i'm getting the following
error:

System.ServiceModel.CommunicationException: There was an error while trying
to serialize parameter http://tempuri.org/bj. The InnerException message
was 'Type 'WCFSharedLib.TestObject' with data contract name
'TestObject:http://schemas.datacontract.org/2004/07/WCFSharedLib' is not
expected. Add any types not known statically to the list of known types - for
example, by using the KnownTypeAttribute attribute or by adding them to the
list of known types passed to DataContractSerializer.'. Please see
InnerException for more details. --->
System.Runtime.Serialization.SerializationException: Type
'WCFSharedLib.TestObject' with data contract name
'TestObject:http://schemas.datacontract.org/2004/07/WCFSharedLib' is not
expected. Add any types not known statically to the list of known types - for
example, by using the KnownTypeAttribute attribute or by adding them to the
list of known types passed to DataContractSerializer.\r\n at
System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeAndVerifyTyp
e(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj,
Boolean verifyKnownType)\r\n at
System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithXsiTypeAtTopLevel(DataContract
dataContract, XmlWriterDelegator xmlWriter, Object obj)\r\n at
System.Runtime.Serialization.DataContractSerializer.InternalWriteObjectContent(XmlWriterDelegator
writer, Object graph)\r\n at
System.Runtime.Serialization.DataContractSerializer.InternalWriteObject(XmlWriterDelegator
writer, Object graph)\r\n at
System.Runtime.Serialization.XmlObjectSerializer.WriteObjectHandleExceptions(XmlWriterDelegator
writer, Object graph)\r\n at
System.Runtime.Serialization.XmlObjectSerializer.WriteObject(XmlDictionaryWriter
writer, Object graph)\r\n at
System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeParameterPart(XmlDictionaryWriter
writer, PartInfo part, Object graph)\r\n --- End of inner exception stack
trace ---\r\n\r\nServer stack trace: \r\n at System.ServiceModel.Di
spatcher.DataContractSerializerOperationFormatter.SerializeParameterPart(XmlDictionaryWriter
writer, PartInfo part, Object graph)\r\n at
System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeParameter(XmlDictionaryWriter
writer, PartInfo part, Object graph)\r\n at
System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeParameters(XmlDictionaryWriter
writer, PartInfo[] parts, Object[] parameters)\r\n at
System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeBody(XmlDictionaryWriter
writer, MessageVersion version, String action, MessageDescription
messageDescription, Object returnValue, Object[] parameters, Boolean
isRequest)\r\n at
System.ServiceModel.Dispatcher.OperationFormatter.SerializeBodyContents(XmlDictionaryWriter
writer, MessageVersion version, Object[] parameters, Object returnValue,
Boolean isRequest)\r\n at
System.ServiceModel.Dispatcher.OperationFormatter.OperationFormatterMessage.OperationFormatterBodyWriter.On
WriteBodyContents(XmlDictionaryWriter writer)\r\n at
System.ServiceModel.Channels.BodyWriter.WriteBodyContents(XmlDictionaryWriter
writer)\r\n at
System.ServiceModel.Channels.BodyWriterMessage.OnWriteBodyContents(XmlDictionaryWriter
writer)\r\n at
System.ServiceModel.Channels.Message.WriteBodyContents(XmlDictionaryWriter
writer)\r\n at
System.ServiceModel.Security.SecurityAppliedMessage.WriteBodyToSignThenEncryptWithFragments(Stream
stream, Boolean includeComments, String[] inclusivePrefixes, EncryptedData
encryptedData, SymmetricAlgorithm algorithm, XmlDictionaryWriter writer)\r\n
at
System.ServiceModel.Security.WSSecurityOneDotZeroSendSecurityHeader.ApplyBodySecurity(XmlDictionaryWriter
writer, IPrefixGenerator prefixGenerator)\r\n at
System.ServiceModel.Security.SecurityAppliedMessage.OnWriteMessage(XmlDictionaryWriter
writer)\r\n at
System.ServiceModel.Channels.Message.WriteMessage(XmlDictionaryWriter
writer)\r\n at
System.ServiceModel.Channels.BufferedMessageWriter.WriteMessage(Message mes
sage, BufferManager bufferManager, Int32 initialOffset, Int32
maxSizeQuota)\r\n at
System.ServiceModel.Channels.TextMessageEncoderFactory.TextMessageEncoder.WriteMessage(Message
message, Int32 maxMessageSize, BufferManager bufferManager, Int32
messageOffset)\r\n at
System.ServiceModel.Channels.MessageEncoder.WriteMessage(Message message,
Int32 maxMessageSize, BufferManager bufferManager)\r\n at
System.ServiceModel.Channels.HttpOutput.SerializeBufferedMessage(Message
message)\r\n at System.ServiceModel.Channels.HttpOutput.Send(TimeSpan
timeout)\r\n at
System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.SendRequest(Message
message, TimeSpan timeout)\r\n at
System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan
timeout)\r\n at
System.ServiceModel.Channels.ClientReliableChannelBinder`1.RequestClientReliableChannelBinder`1.OnRequest(TRequestChannel
channel, Message message, TimeSpan timeout, MaskingMode maskingMode)\r\n at
System.ServiceModel.
Channels.ClientReliableChannelBinder`1.Request(Message message, TimeSpan
timeout, MaskingMode maskingMode)\r\n at
System.ServiceModel.Channels.ClientReliableChannelBinder`1.Request(Message
message, TimeSpan timeout)\r\n at
System.ServiceModel.Security.SecuritySessionClientSettings`1.SecurityRequestSessionChannel.Request(Message
message, TimeSpan timeout)\r\n at
System.ServiceModel.Dispatcher.RequestChannelBinder.Request(Message message,
TimeSpan timeout)\r\n at
System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean
oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs,
TimeSpan timeout)\r\n at
System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean
oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs)\r\n
at
System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage
methodCall, ProxyOperationRuntime operation)\r\n at
System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage
message)\r\n\r\nException reth
rown at [0]: \r\n at
System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage
reqMsg, IMessage retMsg)\r\n at
System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData,
Int32 type)\r\n at ISomeContract.Blah(DBObject obj)\r\n at
SomeContractClient.Blah(DBObject obj) in
C:\\Projects\\Junk\\WCFInterfaceTest\\WCFSharedLib\\WCFProxy.cs:line 213\r\n
at WCFInterfaceTest.Form1.button1_Click(Object sender, EventArgs e) in
C:\\Projects\\Junk\\WCFInterfaceTest\\WCFInterfaceTest\\Form1.cs:line 28"


"Ronald Ramirez Moran" wrote:

Ok, I found the answer to the problem. Turns out there is another serializer
that is specialized for .NET to .NET communication using the WCF framework.
It is called the NetDataContractSerializer. This serializer embeds the CLR
Type in the Message so that it can be reconstructed on the other end. Here
is the link to Avner Kashtan's blog which has the resolution and a link to
Aaron Skonnard's blog who provides the attribute code to change the
serializer from DataContractSerializer to NetDataContractSerializer.

http://weblogs.asp.net/avnerk/archiv...erializer.aspx

"Matthew Yost" wrote:

The attributes ServiceKnownTypeAttribute and KnownTypeAttribute, must be
applied to the Service Contract or ServiceImplementation.

This is important, because the ServiceContract needs to know, how to
serialize the messages. The class must be marked with a
SerializableAttribute or DataContractAttribute attributes.

Regards,

--
Ronald Ramirez Moran (aka DlanorOk)
Personal Space: http://dlanorok.spaces.live.com
Blog: http://ecuador.latindevelopers.net/blogs/dlanorok
--

"Matthew Yost" <MatthewYost@xxxxxx> wrote in message
news:22B05DB6-8FC1-4909-8840-C8B6D20FD091@xxxxxx