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Registered: ‎03-25-2013
Post 1 of 2

Best practice with MVVM

267 Views, 1 Replies
07-08-2013 04:37 AM

I'm on a project that will have about a dozen of commands. Where should I put them?


For each viewmodel I have a view and a main model.

My commands only show the views, so it would make sense to be in the View part of the MVVM. But, if I put the command in the view's codebehind, autocad would instantiate the view for the whole lifetime of the document and I don't want this.

If I create a separate class for each command using a naming system like NameOfTheViewCommand, then I would practically have an MVVMC pattern, where C stand for command.

Or maybe I should create a class which includes all my commands and nothing else?

Or maybe all these approaches are wrong and there's already a well-established pattern known only by Autocad .NET experts and one of these gurus is kind enough to provide a best practice guide for this matter?

ADN Support Specialist
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Registered: ‎07-24-2007
Post 2 of 2

Re: Best practice with MVVM

07-11-2013 09:33 AM in reply to: andreiim

in terms of AutoCAD, we have a 3 level split...


1) Dependency on acad.exe

   - define your commands that rely on the AutoCAD UI here

2) Dependency on accore.dll

  - define your commands that only require the command line to work

3) Dependency on acdb19.dll

  - define your DWG manipulate code here


I recommend that all of your commands define a UI version and a non-UI version - e.g. LAYER (UI) -LAYER command line only. Your UI version should be in a DLL which references acmgd.dll (acad.exe), acdbmgd.dl (acdb19.dlll and accoremgd.dll (accore.dll)


I recommend that all of your -LAYER defined commands should be in a DLL which references accoremgd.dll, acdbmgd.dll


I recommend all of your DB related functionality reside in a DLL which references acdbmgd.dll.


Doing this will ensure:


1) Your commands can be scripted

2) Your commands will work on the cloud

3) Your code will work in other non-AutoCAD DWG hostable applications (RealDWG enabled)

Fenton Webb

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