Hi,

It is a bit unclear do you mean directly in a node Value (i.e. you give the ‘structure-array’ directly to Variant) or do you have a Structure that has the structure-array as a field. Since you do mention “2 arrays” and “index field”, maybe the latter, but that too was more about “work at all conceptually” so I’m not sure. Though, both ways should work, but the latter one needs probably more explanations.

In the case of having the structure-array directly in a node (i.e. you use it to make the Value Variant). Structures within Variant are encoded (in the binary transit) as ExtensionObjects (builtintype 22). An array of Structures becomes an array of ExtensionObjects, basically each element has their own type info (as part of the ExtensionObject encoding). This also has the side-effect that on the “encodings-level” an empty array of structures doesn’t have a type (SDK patches this info in some cases once we are in the “node datatype level”). Also, the decoder will choose the most-subtyped version of the array that can fit the elements. Thus if they are all MyStructuredSubDataTypeB then it is MyStructuredSubDataTypeB[] (which might cause issues if you then try to assign MyStructuredSubDataTypeA). Could be some room for improvements..

In the case of having the structure-array as a field in a structure, it should work, but you must either have a “normal structure” and i=22 (the raw ‘Structure’ DataType) as the field type OR have a “StructureWithSubtypedValues structure” and mark the field as AllowSubTypes true and then have the base MyStructredBaseDataType as the field DataType. However! Note that Codegen will create an ExtensionObject[] field in both cases. This is because currently generated structure types in the SDK cannot represent their subtypes and it is possible a non-generated model extends a generated Structure thus it would be impossible java-wise to set ‘DynamicStructure’ representing the non-generated subtype as an element of a generated structure type array (ExtensionObject is the only thing that can handle both). Thus you will need to handle this data as ExtensionObject[] and take the structures by ExtensionObject.getObject() (they should be decoded as long as the client knows the types either by codegen or has read them during connect).

Hmm.. seems UaExpert is better in this regard, I’ll mark this as an improvement idea for Browser. Like technically the data is visible in the tooltip (or if you copy it to clipboard), though this is mostly a side-effect (of ExtensionObject.toString), anyway not very usable… but we should probably show it the same way (or make it expandable at least).