CODEWITHSUNDEEP
streamwcffilestream
David
David

Reputation: 830

ArgumentNullException when streaming files via WCF

I have a WCF streaming binary files. Below is a shortened version of the contract.

[MessageContract()]
public class DocumentTransfer
{
    [MessageHeader(MustUnderstand = true)]
    public string Title { get; set; }

    [MessageHeader(MustUnderstand = true)]
    public string FileName { get; set; }

    [MessageBodyMember(Order = 1)]
    public System.IO.Stream Data;
}

Everything works fine but there are scenarios when only some other values associated with the file need to be updated but not the file itself. In that case the client sets Data = null. The Data property then cannot be interpreted/serialized and throws this exception:

System.ServiceModel.Dispatcher.StreamFormatter.Serialize(XmlDictionaryWriter writer, Object[] parameters, Object returnValue)
System.ServiceModel.Dispatcher.OperationFormatter.SerializeBodyContents(XmlDictionaryWriter writer, MessageVersion version, Object[] parameters, Object returnValue, Boolean isRequest)
System.ServiceModel.Dispatcher.OperationFormatter.OperationFormatterMessage.OperationFormatterBodyWriter.OnWriteBodyContents(XmlDictionaryWriter writer)
System.ServiceModel.Channels.BodyWriter.WriteBodyContents(XmlDictionaryWriter writer)
System.ServiceModel.Channels.BodyWriterMessage.OnWriteBodyContents(XmlDictionaryWriter writer)
System.ServiceModel.Channels.Message.OnWriteMessage(XmlDictionaryWriter writer)
System.ServiceModel.Channels.Message.WriteMessage(XmlDictionaryWriter writer)
System.ServiceModel.Channels.TextMessageEncoderFactory.TextMessageEncoder.WriteMessage(Message message, Stream stream)
System.ServiceModel.Channels.HttpOutput.WriteStreamedMessage(TimeSpan timeout)
System.ServiceModel.Channels.HttpOutput.Send(TimeSpan timeout)
System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.SendRequest(Message message, TimeSpan timeout)
System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan timeout)
System.ServiceModel.Dispatcher.RequestChannelBinder.Request(Message message, TimeSpan timeout)
System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs)
System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)
System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
...UploadDocument(DocumentTransfer request)
...UploadDocument(DocumentTransfer request) in ...

Any ideas guys?

Upvotes: 3

Views: 682

Answers (2)

Matthew Cole
Matthew Cole

Reputation: 1339

Another option would be to return Stream.Null.

Upvotes: 2

Shiraz Bhaiji
Shiraz Bhaiji

Reputation: 65491

You are getting the error in SerializeBodyContents when the body is null.

You can either create a different operation for when you do not have a file, or put a byte in the stream to avoid the exception. The first of these options is preferable, the last if you cannot change the contract.

Upvotes: 2

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