Topic: Tell whether blockreference is an xref

[Bernd]

Is there a way to tell whether a BlockReference is an xref or a "normal" block?
Background is that I'm transforming all objects in a drawing except XRefs as they reference already transformed drawings.

Thanks, Bernd

[huiz]

A BlockTableRecord has a property named IsFromExternalReference.


Maybe these links are useful:


http://adndevblog.typepad.com/autocad/2012/07/changing-xref-paths-from-absolute-to-relative.html


http://adndevblog.typepad.com/autocad/2012/06/finding-all-xrefs-in-the-current-database-using-cnet.html

[Bernd]

Sounds good - I'll check it out next week.
Thanks for your help!

[Bernd]

Tried to get something together with the help of your links. But I'm not sure whether my code is fool proof, so I'd appreciate any comment on it...

Code - C#: [Select]

1. using (var blockTable = (BlockTable)trans.GetObject(database.BlockTableId, OpenMode.ForRead))
2. using (var modelSpace = (BlockTableRecord)trans.GetObject(blockTable[BlockTableRecord.ModelSpace], OpenMode.ForRead))
3. {
4.     /* Find all XRefs */
5.     var objectIdsXrefs = new ObjectIdCollection();
6.     foreach (ObjectId oid in blockTable)
7.     {
8.         var btr = trans.GetObject(oid, OpenMode.ForRead) as BlockTableRecord;
9.         if (btr.IsFromExternalReference)
10.             objectIdsXrefs.Add(oid);
11.     }
12.  
13.     /* iterate over each graphical object */
14.     foreach (ObjectId oid in modelSpace)
15.     {
16.         using (var dbObject = trans.GetObject(oid, OpenMode.ForRead))
17.         {
18.             if (dbObject is BlockReference)
19.             {
20.                 /* Is the assumption correct, that the blockreference's (xref's) DynamicBlockTableRecord
21.                    is the same id as xref's BlockTableRecord id?
22.                    In my case it is, but could that also be different? */
23.                 if (objectIdsXrefs.Contains(((BlockReference)dbObject).DynamicBlockTableRecord))
24.                     continue;
25.             }
26.             /* else transform the object ... */
27.         }
28.     }
29. }
30.  

Thank you 

[Gasty]

Hi,

From DXF reference:

Code 70

Block-type flags (bit coded values, may be combined):
1 = This is an anonymous block generated by hatching, associative dimensioning, other internal operations, or an application.
2 = This block has non-constant attribute definitions (this bit is not set if the block has any attribute definitions that are constant, or has no attribute definitions at all).
4 = This block is an external reference (xref).
8 = This block is an xref overlay.
16 = This block is externally dependent.
32 = This is a resolved external reference, or dependent of an external reference (ignored on input).
64 = This definition is a referenced external reference (ignored
on input).

Gaston Nunez