How to Access In Memory Copy of XREFs?

[PengYen6809]

In AutoCAD Architecture Options > Open and Save Tab, there are the External Reference (Xrefs) options where by default Demand load Xrefs is “Enabled with Copy”, Retain changes to Xref layers, Allow other users to Refedit current drawing are checked. 

May I enquire how is Xref handled internally by the AutoCAD software? Do AutoCAD internally makes a temporary copy of the referenced files, and hence when there are changes to the referenced files, a reload is required. Do correct my understanding if I am wrong.

If that is the case, may I enquire are there any .NET APIs that are able to access the in memory copy of the referenced DWGs if I am using the “Enabled with Copy” option for the Demand load Xrefs. 

I have tried to change the Xrefs option Demand load Xrefs to “Enabled”, in hoping no file copy will be done, but our application was unable to overwrite the individual level DWG using the SaveAs function due to an eFileViolation error, as AutoCAD software is opening up the referenced DWGs.

If that is the case, may I enquire are there any .NET APIs to allow for AutoCAD Architecture to Save the DWG instead of the Application doing so?

[jeff]

I have not tried with AEC API as the project navigator uses xrefs but with a little more functionality I think.

A xref is like a block and is a BlocktableRecord added to the Blocktable.

What you can do is load the xref in a side database change and save. 

In Aec I have not looked if the path maps to the xml files or to the actual dwg.

Here a a example that lets you draw something in paperspace then sends it to the xref drawing that might be a start.

So some extra code translating from paper to model.

http://www.theswamp.org/index.php?topic=34590.msg398539#msg398539