[CONNECT Update 16 C++] Has Element Property X?

How can we find programmatically whether a DGN element has a particular property?

For example, several elements have a Length property.  It's valid for lines, line-strings, arcs and I believe curve vectors in general.  The picture is blurred because sometimes the property name (not its display name) is Length and sometimes TotalLength. But can I determine that fact programmatically: I'm looking for fictitious method something like HasProperty (ElementHandleR eh, L"className", L"propName")?

In particular, for my current project I want to know whether a DGN element has the Bearing or Azimuth property.  A simple DGN line element has that property, but what other element types?