Problems with WCF deserialising SOAP array containing polymorphic objects - wcf

Question

I have a problem with a WCF web services that is deserialising an array of polymorphic objects. The server side is not WCF, but I created the stubs from WSDL. The important parts in WSDL are
<complexType name="NodeList">
<sequence>
<element name="data" type="cmtypes:Node" minOccurs="0" maxOccurs="unbounded" nillable="true"/>
</sequence>
</complexType>
and
<complexType name="Device">
<sequence>
<element name="uniqueKey" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
<element name="revision" type="xsd:string" minOccurs="1" maxOccurs="1"/>
[...}
</sequence>
</complexType>
<complexType name="Node">
<complexContent>
<extension base="cmtypes:Device">
<sequence>
<element name="cmdaemonUrl" type="xsd:string" minOccurs="1" maxOccurs="1"/>
<element name="networks" type="cmtypes:NetworkInterfaceList" minOccurs="0" maxOccurs="1" nillable="true"/>
[...]
</sequence>
</extension>
</complexContent>
</complexType>
<complexType name="MasterNode">
<complexContent>
<extension base="cmtypes:Node">
<sequence>
</sequence>
</extension>
</complexContent>
</complexType>
VS created the following type for the list:
[System.Xml.Serialization.SoapIncludeAttribute(typeof(MasterNode))]
[System.Xml.Serialization.SoapIncludeAttribute(typeof(SlaveNode))]
[System.Xml.Serialization.SoapIncludeAttribute(typeof(VirtualSMPNode))]
[System.Xml.Serialization.SoapIncludeAttribute(typeof(VirtualNode))]
[System.Xml.Serialization.SoapIncludeAttribute(typeof(PhysicalNode))]
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Xml", "4.0.30319.233")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.SoapTypeAttribute(Namespace="http://www.brightcomputing.com/cmtypes.xsd")]
public partial class Node : Device {
private string cmdaemonUrlField;
[...]
}
However, if I receive a message containing a master node like
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://www.w3.org/2003/05/soap-envelope" xmlns:SOAP-ENC="http://www.w3.org/2003/05/soap-encoding" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:cmtypes="http://www.brightcomputing.com/cmtypes.xsd" xmlns:cmdevice="http://www.brightcomputing.com/cmdevice.wsdl">
<s:Header xmlns:s="http://www.w3.org/2003/05/soap-envelope"></s:Header>
<SOAP-ENV:Body>
<cmdevice:getNodesResponse SOAP-ENV:encodingStyle="http://www.w3.org/2003/05/soap-encoding">
<nodes xsi:type="cmtypes:NodeList" xmlns="">
<data xsi:type="cmtypes:MasterNode">
<uniqueKey xsi:type="xsd:unsignedLong">38654705666</uniqueKey>
<revision xsi:type="xsd:string"></revision>
<modified xsi:type="xsd:boolean">false</modified>
<toBeRemoved xsi:type="xsd:boolean">false</toBeRemoved>
[...]
the whole stuff explodes with a System.ServiceModel.CommunicationException saying "Error in deserializing body of reply message for operation 'getNodes'." and "Object cannot be stored in an array of this type." in the inner exception. Why? What can I do to fix this (the stub generation)?
I have absolutely no clue due to very limited WCF/SOAP knowledge, so any help is appreciated.
Best regards,
Christoph
Edit: It might be relevant that the response actually contains "data" elements of different, polymorphic types, i.e. cmtypes:MasterNode and cmtypes:PhysicalNode.
Edit: Could it be that the Stub and the Message do not go together? As I understand, the stub expects a data property, which is an array:
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Xml", "4.0.30319.233")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.SoapTypeAttribute(Namespace="http://www.brightcomputing.com/cmtypes.xsd")]
public partial class NodeList : object, System.ComponentModel.INotifyPropertyChanged {
private Node[] dataField;
/// <remarks/>
[System.Xml.Serialization.SoapElementAttribute(IsNullable=true)]
public Node[] data {
get {
return this.dataField;
}
set {
this.dataField = value;
this.RaisePropertyChanged("data");
}
}
public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;
protected void RaisePropertyChanged(string propertyName) {
System.ComponentModel.PropertyChangedEventHandler propertyChanged = this.PropertyChanged;
if ((propertyChanged != null)) {
propertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(propertyName));
}
}
}
However, in my answer I get a NodeList directly containing a sequence of data elements, which are actually nodes or derived from nodes:
<cmdevice:getNodesResponse SOAP-ENV:encodingStyle="http://www.w3.org/2003/05/soap-encoding">
<nodes xsi:type="cmtypes:NodeList" xmlns="">
<data xsi:type="cmtypes:MasterNode">
<uniqueKey xsi:type="xsd:unsignedLong">38654705666</uniqueKey>
[...]
</data>
<data xsi:type="cmtypes:PhysicalNode">
<uniqueKey xsi:type="xsd:unsignedLong">38654705669</uniqueKey>
[...]
</data>
[...]
Do you think I can fix that somehow by injecting a behavior in WCF? My big problem is that I have absolutely no possibility of chaning the server side...

Answer 1

Troubleshooting this is going to be hard. One thing I would try is using XmlSerializer to see if it can deserialize then start reducing the message until you get the offending type.