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Creating managed wrapper for custom entity

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By Balaji Ramamoorthy

ObjectARX 2009 SDK had a nice sample project called “SimpleSquare” that demonstrated the managed wrapper creation that allows access to the custom entity from a managed code. I have migrated this sample project to work with AutoCAD 2013 and Visual Studio 2010.

The changes are mainly to conform to the new CLR syntax as the original sample used the old CLR syntax.  

Here is the sample project for download.

Download SimpleSquare

To try this, place the “SimpleSquare” folder under “<ObjectARX 2013 SDK folder>\samples\entity” and follow the steps explained in the ReadMe.txt

Comments

20 responses to “Creating managed wrapper for custom entity”

  1. Tony Tanzillo Avatar
    Tony Tanzillo

    Hi Balaji.
    Your sample (and the original) are missing some very important things.
    You can read more about that in this discussion group post:
    http://forums.autodesk.com/t5/Autodesk-ObjectARX/data-extraction-wizzard-custom-entity/m-p/2180119/highlight/true#M24034

    Reply
  2. Dale Bartlett Avatar
    Dale Bartlett

    Hi Balaji, I am unable to load the solution into VS2010 Express, nor the SimpleSquare.vcproj separately. It attempts to upgrade and then fails. Just curious if this has happened for others.

    Reply
  3. Balaji Avatar
    Balaji

    Hi Tony,
    Thanks for that informative link.
    It will help developers interested in using Data extraction with custom entity.

    Reply
  4. Balaji Avatar
    Balaji

    Sorry, I havent tried it with Visual Studio Express edition.
    It is not a supported compiler for ObjectARX applications and some restriction do apply when you use it.
    http://adndevblog.typepad.com/autocad/2012/05/about-visual-studio-2010-visual-studio-express-platform-toolset-and-autocad-2010-2012.html

    Reply
  5. Tony Tanzillo Avatar
    Tony Tanzillo

    Hi Balaji.
    You’re welcome.
    However, I think it’s important to not marginalize the issue.
    Supporting data extraction is not a ‘luxury’ but rather a necessity, hence the need for a basic example of a managed wrapper for a custom entity to show how to do that.

    Reply
  6. Dale Bartlett Avatar
    Dale Bartlett

    Thanks Balaji, I’ll test on VS Professional version.

    Reply
  7. Balaji Avatar
    Balaji

    Sorry, My intention was not to marginalize the issue. It is indeed important to have the DX correctly extract data from a custom entity. As you have already provided the link to help developers understand the changes that need to go into this sample project, I did not mention about changing the sample itself.
    Regards,
    Balaji

    Reply
  8. Tony Tanzillo Avatar
    Tony Tanzillo

    Balaji, No problem.
    It would be nice if the distributed sample, or any sample, showed how to support Data Extraction. I’ve already come across quite a few cases where custom objects (including some from AutoCAD-based products) do not support Data Extraction, and most-definitely should.

    Reply
  9. Larry Rios Avatar
    Larry Rios

    Balaji,
    Will the new clr syntax work with AutoCAD 2010 SDK?
    Thanks,
    Larry

    Reply
  10. Balaji Avatar
    Balaji

    Hi Larry,
    Yes, the sample project in the blog post also works with AutoCAD 2010. The .Net framework version will need to be changed to v3.5 by manually changing the “SimpleSquare.vcxproj” file as explained in this post :
    http://stackoverflow.com/questions/2921702/change-c-cli-project-to-another-framework-than-4-0-with-vs2010
    The “SimpleSquareUI” project will need to target 3.5 which can be modified using the project properties in Visual Studio IDE.
    Regards,
    Balaji

    Reply
  11. Carl Avatar
    Carl

    Balaji,
    Can you point me to any links that pass strings through the managed wrapper? it seems like such a simple thing, but unicode makes it not so ;) Cheers!

    Reply
  12. Balaji Avatar
    Balaji

    Hi Carl,
    Can you please refer to the \Samples\Entity\PolySamp example ?
    It uses the “StringToCIF” and “CIFToString” methods to pass strings to and forth.
    Regards,
    Balaji

    Reply
  13. Carl Avatar
    Carl

    thanks! I’ve been digging through that but it’s huge – and easy to miss. I’m off and running now.
    This is the second time (at least) you bailed me out personally, so thanks again :)

    Reply
  14. Carl Avatar
    Carl

    A quick clarification on syntax:
    SimpleSquare uses
    property type name
    {
    get
    set
    }
    notation, while PolySamp uses
    __property void set_Center(Point2d point);
    and I originally based mine on SimpleSquare – learning from PolySamp as I go. anyway, my notation pulls an error on String* (no pointers in c++/cli etc) and the __Property notation doesn’t work either… Can I use the both property declarations to pass a string or am I missing something here?

    Reply
  15. Carl Avatar
    Carl

    ps, I’ve started a discussion about this here:
    http://forums.autodesk.com/t5/Autodesk-ObjectARX/passing-string-to-custom-objects-through-a-managed-wrapper/m-p/4668155
    so as to not derail things here.

    Reply
  16. Balaji Avatar
    Balaji

    Hi Carl,
    Can you please check if your project is using the old clr syntax or the new one ?
    You can find the difference in the syntax here :
    http://msdn.microsoft.com/en-us/library/b23b94s7(v=vs.90).aspx
    Regards,
    Balaji

    Reply
  17. Paul Coulson Avatar
    Paul Coulson

    This is a great example. How would I expose virtual functions such as subWorldDraw() to .NET in the managed wrapper, so that they can be overridden by classes derived from MgSimpleSquare?

    Reply
  18. Balaji Avatar
    Balaji

    Hi,
    Implementing a custom entity derived from other entity types is not an option that is available with the AutoCAD .Net API. The sample project in this blog post only provides a way to instantiate and set properties of the custom entity through its managed wrapper. I think, you can consider DrawableOverrule and see if that will be of any help in customizing the worldDraw of an entity.
    Regards,
    Balaji

    Reply
  19. GlacierXie Avatar
    GlacierXie

    I want to know how to get/set collection dat？I used List,but not work~

    Reply
  20. Subir Dutta Avatar
    Subir Dutta

    I got a drawing with Custom Entities and also got the Object Enablers. So now the entities show up in the drawing. Now is it possible to read the properties of the Custom Entities through .Net API ?
    My best guess is, the developer of the Custom Entity need to take care about exposing the properties so that those properties can be accessed by .Net API. Am I correct ? Now I don’t have anything excepts the object enablers ( dbx ). How to proceed ?

    Reply

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