[CONNECT .NET] Get value of MicroStation global variable

Hi Jon,

Jon Summers said:

How do I use a C++ global variable when writing a .NET AddIn?

I think you have to use the same approach as for an access of C++ API: To use P/Invoke or C++/CLI and to implement own wrapper.

Regards,

  Jan

Hi Jon Summers,

Primarily for legacy published variable access from .NET addins the cleanest implementation would be calling GetCExpression/SetCExpression via Bentley.Interop.MicroStationDGN.Application (MicroStation VBA COM wrappers). Next would be as Jan suggestions C++/CLI helper methods that could provide similar clean calling conventions and better performance.

Lastly, though more work required and fewer code snips/examples available, either: EC (IECInstance > IECSchema > IECClass StringValue) or BIM.NamedExpressionManager (see this post) permit you to access and/or publish via NamedExpressions.

HTH,
Bob

[UPDATE-20210510-RH] MSCE SDK provides a v0811 NamedExpression example under: ..\Documentation\Migration\Workshop\Labs\MigrationTesting\v0811\dotnet\examples\NamedExprTest\NamedExprApp.cs

Jan Šlegr said:

I think you have to use the same approach as for an access of C++ API: To use P/Invoke

There is no way I can find to use P/Invoke with a global variable.

Jan Šlegr said:

Use C++/CLI and to implement own wrapper

That seems arduous simply to find the value of a global integer variable.  But it may be my only recourse.

Robert Hook said:

The cleanest implementation would be calling GetCExpression/SetCExpression

Thanks for that suggestion.  The C expression parser enables read/write access to C++ global var mgds_modes.always_open_readonly.

You're welcome and glad it helped.

Bob