Posted in Dynamics 365

Dynamics 365: Web Service plug-in failed – Invalid name character in ‘List`1’ when using Shared Variables

Hi

Recently I had an issue with D365 plug-ins and it took me a lot of investigation and trial & error to figure out the problem.

I will start by explaining my scenario:

  • Dynamics 365 v8.2 on-premise
  • Plug-in registered on the Update message and Pre-Validation execution pipeline
  • Plug-in registered on the Update message and Pre-Operation execution pipeline
  • Also my Pre-Validation plug-in passes two Shared Variables to my Pre-Operation plug-in

If you are not familiar with Shared Variables in plug-ins, they are a great way to pass values through custom code without having to read D365 data again. It is also a great way to avoid infinite loops. Take a look at the documentation for more details: https://docs.microsoft.com/en-us/dynamics365/sales-enterprise/developer/custom-plugin-handling-shared-variable.

When triggering the plug-in via my application, it threw a very weird exception and for some reason I couldn’t debug my plug-in (a serialization error would come up and not log into the profiler). After a while troubleshooting, I found the below error in the Event Viewer in D365 Server:

The Web Service plug-in failed in OrganizationId: 466f6c23-6896-e811-a824-005056a99671; SdkMessageProcessingStepId: 4d51b0c7-d9c4-ea11-b81d-005056a75ee5; EntityName: contact; Stage: 30; MessageName: Update; AssemblyName: Microsoft.Crm.Extensibility.InternalOperationPlugin, Microsoft.Crm.ObjectModel, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35; ClassName: Microsoft.Crm.Extensibility.InternalOperationPlugin; Exception: Unhandled Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
   at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Web.Services.Protocols.LogicalMethodInfo.Invoke(Object target, Object[] values)
   at Microsoft.Crm.Extensibility.InternalOperationPlugin.Execute(IServiceProvider serviceProvider)
   at Microsoft.Crm.Extensibility.V5PluginProxyStep.ExecuteInternal(PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.VersionedPluginProxyStepBase.Execute(PipelineExecutionContext context)
Inner Exception: System.ArgumentException: Invalid name character in 'List`1'. The '`' character, hexadecimal value 0x60, cannot be included in a name.
   at System.Xml.XmlWellFormedWriter.CheckNCName(String ncname)
   at System.Xml.XmlWellFormedWriter.WriteQualifiedName(String localName, String ns)
   at System.Runtime.Serialization.XmlWriterDelegator.WriteAttributeQualifiedName(String attrPrefix, XmlDictionaryString attrName, XmlDictionaryString attrNs, XmlDictionaryString name, XmlDictionaryString ns)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.WriteTypeInfo(XmlWriterDelegator writer, XmlDictionaryString dataContractName, XmlDictionaryString dataContractNamespace)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.WriteTypeInfo(XmlWriterDelegator writer, DataContract contract, DataContract declaredContract)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithXsiType(XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle objectTypeHandle, Type objectType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, Type declaredType)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerialize(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerializeReference(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at WriteKeyValuePairOfstringanyTypeToXml(XmlWriterDelegator , Object , XmlObjectSerializerWriteContext , ClassDataContract )
   at System.Runtime.Serialization.ClassDataContract.WriteXmlValue(XmlWriterDelegator xmlWriter, Object obj, XmlObjectSerializerWriteContext context)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.WriteDataContractValue(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithoutXsiType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerialize(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at WriteParameterCollectionToXml(XmlWriterDelegator , Object , XmlObjectSerializerWriteContext , CollectionDataContract )
   at System.Runtime.Serialization.CollectionDataContract.WriteXmlValue(XmlWriterDelegator xmlWriter, Object obj, XmlObjectSerializerWriteContext context)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.WriteDataContractValue(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithoutXsiType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerialize(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerializeReference(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at WriteAsyncOperationDataToXml(XmlWriterDelegator , Object , XmlObjectSerializerWriteContext , ClassDataContract )
   at System.Runtime.Serialization.ClassDataContract.WriteXmlValue(XmlWriterDelegator xmlWriter, Object obj, XmlObjectSerializerWriteContext context)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.WriteDataContractValue(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithoutXsiType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerialize(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerializeReference(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at WriteAsyncOperationDataToXml(XmlWriterDelegator , Object , XmlObjectSerializerWriteContext , ClassDataContract )
   at System.Runtime.Serialization.ClassDataContract.WriteXmlValue(XmlWriterDelegator xmlWriter, Object obj, XmlObjectSerializerWriteContext context)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.WriteDataContractValue(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithoutXsiType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerialize(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerializeReference(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at WriteAsyncOperationDataToXml(XmlWriterDelegator , Object , XmlObjectSerializerWriteContext , ClassDataContract )
   at System.Runtime.Serialization.ClassDataContract.WriteXmlValue(XmlWriterDelegator xmlWriter, Object obj, XmlObjectSerializerWriteContext context)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.WriteDataContractValue(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithoutXsiType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerialize(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerializeReference(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at WriteAsyncOperationDataToXml(XmlWriterDelegator , Object , XmlObjectSerializerWriteContext , ClassDataContract )
   at System.Runtime.Serialization.ClassDataContract.WriteXmlValue(XmlWriterDelegator xmlWriter, Object obj, XmlObjectSerializerWriteContext context)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.WriteDataContractValue(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithoutXsiType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.DataContractSerializer.InternalWriteObjectContent(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver)
   at System.Runtime.Serialization.DataContractSerializer.InternalWriteObject(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver)
   at System.Runtime.Serialization.XmlObjectSerializer.WriteObjectHandleExceptions(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver)
   at Microsoft.Crm.Extensibility.AsynchronousStep.SerializeAsyncData(PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.AsynchronousStep.Execute(PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.PipelineInstrumentationHelper.Execute(Boolean instrumentationEnabled, String stopwatchName, ExecuteWithInstrumentation action, PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.Pipeline.Execute(PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.PipelineInstrumentationHelper.Execute(Boolean instrumentationEnabled, String stopwatchName, ExecuteWithInstrumentation action, PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.MessageProcessor.Execute(PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.InternalMessageDispatcher.Execute(PipelineExecutionContext context)
   at Microsoft.Crm.Extensibility.ExtensiblePlatformMessageDispatcher.Execute(PipelineExecutionContext pluginContext)
   at Microsoft.Crm.Extensibility.ExtensiblePlatformMessageDispatcher.UpdateWithInvocationSource(BusinessEntity entity, FilterExpression filter, Int32 invocationSource, ExecutionContext context)
   at Microsoft.Crm.Extensibility.ExtensiblePlatformMessageDispatcher.Update(BusinessEntity entity, FilterExpression filter, ExecutionContext context)
   at Microsoft.Crm.BusinessEntities.BusinessProcessObject.UpdateWithPipelineAndExtensions(IBusinessEntity entity, ExecutionContext context)
   at Microsoft.Crm.BusinessEntities.BusinessProcessObject.Update(IBusinessEntity entity, ExecutionContext context)
.

The above error message doesn’t really help much as it happens in an internal plug-in.

Also this sentence from the error message didn’t make a lot of sense (at first): Invalid name character in ‘List`1’. The ‘`’ character, hexadecimal value 0x60, cannot be included in a name.

In my code I wasn’t referencing anything that could have a “`” or any other special character that could be messing things up. My code in the pre-validation plug-in was running correctly and I was able to debug it, I just couldn’t debug the pre-operation one.

After a while troubleshooting and nearly giving up, a colleague suggested that I play around with the Shared Variables I was passing between the plugins and bang!!! That was the issue…

I had two values passing via Shared Variables:

  • GUID – created in the Pre-Validation step
  • List<Entity> – records retrieved in the Pre-Validation step

When removing the List object from my Shared Variables, my plug-in started working with no issues and I could even debug my Pre-Operation plug-in.

Why does this happen?

The issue happens due to how the C# language names a generic list object. Running the simple code below, the exception starts making sense:

            List<string> myList = new List<string>();

            myList.Add("value 01");
            myList.Add("value 02");
            myList.Add("value 03");

            foreach (var item in myList)
            {
                Console.WriteLine(item);
            }

            Console.WriteLine(myList.ToString());

Internally, D365 is probably trying to convert the list object into a string (myList.ToString()) to be used in the next plug-in, and due to the special character created by C#, it throws an exception that Dynamics 365 can’t handle.

Conclusion

The conclusion for this is very simple, don’t pass a list of objects via Shared Variables in plug-ins. In my case, I decided to change the retrieve to the Pre-Operation plug-in. Another thing you can try is an array of GUIDs or other array types, just not a generic C# list object.