Introduction

The MicroStation Development Library (MDL) and MicroStationAPI provide APIs for developers wanting to create custom applications for MicroStation^® from Bentley Systems. We create a MicroStation application as a DLL, written using C++ and built with the Microsoft C++ compiler and linker provided with Visual Studio.

When editing your source code, you can choose whether to use Microsoft Visual Studio, Microsoft Visual Studio Code, or one of your favourite text editors.

When building your app, you can use Visual Studio or the Bentley Systems make (bmake) tools.

Iterating Reference Attachments in a DGN Model

A MicroStation DGN model may have other models attached as references. References may be directly attached to the active model. References may be attached to other references, making a nested structure.

In the topics that follow, I'll show some MicroStationAPI collections and the MDL function family each replaces.

Object	Description	Example
Reachable ModelRef Collection	A list of references attached to a model	Reachable ModelRef Collection Example

Reachable ModelRef Collection

#include <DgnPlatform/DgnModelRef.h>
#include <DgnPlatform/DgnFileIO/DgnModelRefCollections.h>

DgnModelRefR                model = *ISessionMgr::GetActiveDgnModelP ();
ReachableModelRefCollection refs  = model.GetReachableModelRefs ();
for (DgnModelRefP modelRef: refs)
{
  DgnFileP	pFile  = modelRef->GetDgnFileP ();
  DgnModelP	pModel = modelRef->GetDgnModelP ();
  if (pFile && pModel)
  {
    if (modelRef->IsDgnAttachment ())
    {
      // do something with modelRef 
    }
  }
}

Legacy Reference Iteration using MDL

There are two parts to iterating reference attachments: first, enumerate the collection and, second, get information about each attachment.

The mdlModelRefIterator_api is a typical C-style function family. The coder — that's you, dear reader — is responsible for memory-management. When you find an attachment DgnModelRefP, use the mdlRefFile_api to get/set information about that attachment.

DgnModelRefP       rootModel = mdlModelRef_getActive ();
ModelRefIteratorP  iterator;
int                iteratorTypes = MRITERATE_PrimaryChildRefs | MRITERATE_ExtendedChildRefs;
enum               Depth { RootAndPrimaryAttachments = 0, RootAndAllAttachments = -1, };
mdlModelRefIterator_create (&iterator, rootModel, iteratorTypes, RootAndAllAttachments);
while (DgnModelRefP modelRef = mdlModelRefIterator_getNext (iterator))
{
   // do something with modelRef 
   DgnAttachmentP  info = mdlRefFile_getInfo (modelRef);
}
//  don't forget to deallocate memory 
mdlModelRefIterator_free (&iterator);

Back to the Iterator main page.

Questions

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