How to properly use Db.BlockReference and Db.DynBlockReference?

[gswifort]

Are there any rules/best practices for using BlockReference and DynBlockReference? DynBlockReference is a different object than BlockReference because it doesn't have the close, dispose, or cast methods. The rules seem to be the same as using multiple Entity objects – you can have multiple objects for reading, but only one for writing. The problem is that DynBlockReference doesn't throw an error if you instantiate it while a BlockReference object is already open for writing, but calling .getBlockProperties() returns an empty list. It would be helpful to have immediate information when opening a DynBlockReference object, but even if it were possible, it would probably create unnecessary overhead..?

[CEXT-Dan]

AcDbDynBlockReference and AcDbDynBlockTableRecord are helper classes, they’re not AcDbObjects. As far as I know, they only store the ObjectId, which means they must follow the same restrictions of any helper functions that might open a DbObject. There’s really no good way to track the track the open state. Consider

        ref = Db.BlockReference(ref_id)
        dynRef = Db.DynBlockReference(ref_id)
        ref.upgradeOpen()
        dynRef.getBlockProperties() # should fail

Best practice, IMHO is to only leave Db Objects opened for write as short as possible.

        ref = Db.BlockReference(ref_id)
        dynRef = Db.DynBlockReference(ref_id)
        ref.upgradeOpen()
        # do write stuff
        ref.downgradeOpen()
        dynRef.getBlockProperties() # should be ok

or the inverse

        ref = Db.BlockReference(ref_id, Db.OpenMode.kForWrite)
        dynRef = Db.DynBlockReference(ref_id)
        if ref.isWriteEnabled():
            ref.downgradeOpen()
            dynRef.getBlockProperties()
            ref.upgradeOpen()

It would have been nice if AcDbDynBlockReference::getBlockProperties returned an error status

[CEXT-Dan]

I can try to throw, eWasOpenForWrite in getBlockProperties, if that would help
Scratch that, that would have side affects

[CEXT-Dan]

Thinking, I could combine BlockReference and DynBlockReference, or add BlockReference.getBlockProperties, I could make it throw from here if the block is write enabled

[CEXT-Dan]

I added a fresh build to test, you may still need to call downgradeOpen, upgradeOpen., but this should make things easier. I don’t want to call these inside the wrapper as they may have unwanted side affects.

        #eWasOpenForWrite
        #eNotThatKindOfClass = Not Dynamic 

        ref = Db.BlockReference(id)
        print(ref.isDynamicBlock())
        print(ref.getBlockProperties())
        
        ref = Db.BlockReference(id, Db.OpenMode.kForWrite)
        print(ref.isDynamicBlock())
        print(ref.getBlockProperties()) #eWasOpenForWrite

[CEXT-Dan]

ref.isDynamicBlock() returns false if the ref is write enabled, and the block is dynamic, I must add eWasOpenForWrite for all these methods