This pull request modernizes the OPC UA .NET codebase and tests, removes .NET Standard 2.0 support from certificate/security code, and updates test code to use C# 12 and .NET 8+ features for clarity and maintainability.
- Certificate and BouncyCastle interop files (e.g., CertificateBuilder.cs, X509Extensions.cs, X509SignatureFactory.cs) are refactored to drop NETSTANDARD2_0 support and use modern .NET APIs and conditional compilation.
- Test code across the codebase is updated to use default, strongly-typed Parse methods, collection expressions, and improved async/await patterns.
- Exception handling and assertions in tests are modernized, and test method naming is made consistent with Async suffixes.
- The project and build files are updated to clarify Roslynator analyzer usage and remove obsolete netstandard tags.
- General code and test cleanup includes improved null safety, type safety, and removal of deprecated or unused code.
Improvements for complex types.
- Support to encode/decode complex type structures with multidimensional arrays.
- Perf improvements for type loader using new NodeCache fetch multiple interfaces.
- DataTypeDictionary validation when dependencies are used.
- interface for complex type resolver, to build custom types in code.
- improvements of console client to demonstrate browse/read of custom values
+++ Breaking changes +++
IDecoder interface change of the `ReadArray` method
- Return type is now `Array` for all types of arrays. Previously the method returned an array for 1-dim and a `Matrix` type for multidimensional arrays. In addition the convention in generated code is to use `Collection` for all 1-dim arrays, and so was built the `BaseComplexType`. The new convention is to expose the native `Array` type from a complex type, in all cases, hence the return type of `ReadArray` was changed to reflect that for a consistent programming model.
- `ReadArray` has a new parameter `systemType` to efficiently read encodeable types. Previously the `Type` of an encodeable was determined by the encodingid and lookup in the type factory, even when the Type is already known by the caller. The 'old' style is still supported.
- `ReadArray` supports to read encodeable type arrays which are directly encoded in structures. These arrays differ from standard encoding of arrays and they are handled when `BuiltInType.Null` is used as parameter.
Marc Schier