Reading ComplexTypes from Server

[JessevGool]

Type of issue

• Bug
• Enhancement
• Compliance
• Question
• Help wanted

Current Behavior

Currently failing to decode the ExtensionObject into the expected UDT using the following code

 var session = Session.Create(config, new ConfiguredEndpoint(null, selectedEndpoint, EndpointConfiguration.Create(config)), false, "", 60000, null, null).GetAwaiter().GetResult();

 var complexTypeSystem = InitializeComplexTypeSystem(session);
 foreach (var type in complexTypeSystem.GetDefinedTypes())
 {
     Console.WriteLine($"Type Loaded: {type}");
 }
 var result = session.ReadValue("ns=3;s=\"H35dispenser\".\"ID\".\"ElectricalVersion\"");
 Console.WriteLine(result);
 if (result.Value is ExtensionObject extObject)
 {
     Console.WriteLine(extObject.Body.ToString());
     
     var customType = extObject.Body as UDT_SemVer;
     if (customType != null)
     {
         Console.WriteLine($"Successfully read custom UDT: {customType}");
     }
     else
     {
         Console.WriteLine("Failed to decode ExtensionObject into the expected UDT.");
     }
 }
 else
 {
     Console.WriteLine("The result is not an ExtensionObject.");
 }

I have the defined the UDT_SemVer as follows:

 [DataContract(Namespace = "http://www.siemens.com/simatic-s7-opcua")]
 public class UDT_SemVer : IEncodeable, IJsonEncodeable
 {
     #region Constructors
     public UDT_SemVer()
     {
         Initialize();
     }

     [OnDeserializing]
     private void Initialize(StreamingContext context)
     {
         Initialize();
     }

     private void Initialize()
     {
         Major = 0;
         Minor = 0;
         Patch = 0;
     }
     #endregion

     #region Public Properties
     [DataMember(Name = "Major", IsRequired = true, Order = 1)]
     public byte Major { get; set; }

     [DataMember(Name = "Minor", IsRequired = true, Order = 2)]
     public byte Minor { get; set; }

     [DataMember(Name = "Patch", IsRequired = true, Order = 3)]
     public byte Patch { get; set; }
     #endregion

     #region IEncodeable Members
     public ExpandedNodeId TypeId => new ExpandedNodeId("nsu=http://www.siemens.com/simatic-s7-opcua;s=DT_\"UDT_SemVer\"");

     public ExpandedNodeId BinaryEncodingId => new ExpandedNodeId("nsu=http://www.siemens.com/simatic-s7-opcua;s=TE_\"UDT_SemVer\"");

     public ExpandedNodeId XmlEncodingId => new ExpandedNodeId(0);

     public void Encode(IEncoder encoder)
     {
      
         encoder.WriteByte("Major", Major);
         encoder.WriteByte("Minor", Minor);
         encoder.WriteByte("Patch", Patch);
     }

     public void Decode(IDecoder decoder)
     {
         Major = decoder.ReadByte("Major");
         Minor = decoder.ReadByte("Minor");
         Patch = decoder.ReadByte("Patch");
     }

     public bool IsEqual(IEncodeable encodeable)
     {
         if (encodeable is UDT_SemVer other)
         {
             return Major == other.Major && Minor == other.Minor && Patch == other.Patch;
         }
         return false;
     }

     public void EncodeJson(IJsonEncoder encoder)
     {
         encoder.WriteByte("Major", Major);
         encoder.WriteByte("Minor", Minor);
         encoder.WriteByte("Patch", Patch);
     }

     public void DecodeJson(IJsonDecoder decoder)
     {
         Major = decoder.ReadByte("Major");
         Minor = decoder.ReadByte("Minor");
         Patch = decoder.ReadByte("Patch");
     }

     public object Clone()
     {
         return (UDT_SemVer)this.MemberwiseClone();
     }

     public XmlQualifiedName XmlEncodingNamespace => new XmlQualifiedName("http://www.siemens.com/simatic-s7-opcua");

     public ExpandedNodeId JsonEncodingId => throw new NotImplementedException();
     #endregion
 }

The structure looks as follows on the PLC:

And the type that got loaded from the complexTypeSystem = Opc.Ua.ComplexTypes.simatic-s7-opcua.3.UDT_SemVer

I hope this is enough info in order to help me out

Expected Behavior

I expect the extObject.Body to be able to be cast to a UDT_SemVer

Steps To Reproduce

No response

Environment

- OS: Windows 10
- Environment: Visual Studio 2022
- Runtime: .NET 8.0 LTS
- Nuget Version: Latest Stable
- Component: Opc.Ua.Client.ComplexTypes
- Server: Custom Server

Anything else?

No response

[romanett]

@JessevGool To my understanding the Complex type system builds the types at runtime (and uses OPC UA Type BaseComplexType) using the information returned from the OPC UA Server and has no way to know about your implementation of UDT_SemVer. Feel free to propose an extension to allow the loading of own provided types.