Topic: Finding a nested block programmatically in ObjectARX for .Net

[cannorth]

Hello,

   Is there a way to find a block that is nested within another block programmatically in ObjectARX for .Net without iterating through all the blocks?  I don't want the user to select the block themselves either.  I want a method to get a particular block within a block.  The other issue is that there can be multiple parent blocks with the same nested block of the same name in the drawing, so iterating through the block table would find each of the same block.  If you have the parent block of the nested block, is there any way to single out this nested block without selecting others of the same name?

Thanks,

cannorth

[gile]

If you have the parent block of the nested block, is there any way to single out this nested block without selecting others of the same name?

Iterate the parent BlockTableRecord looking for a child BlockReference.

[cannorth]

This is a solution:

  titleblock_id_obj is the object ID of the parent block.

Code: [Select]

                            Dim br1 As BlockReference = trans.GetObject(titleblock_id_obj, AutoCAD.DatabaseServices.OpenMode.ForRead)
                            Dim btr1 As BlockTableRecord = trans.GetObject(br1.BlockTableRecord, AutoCAD.DatabaseServices.OpenMode.ForRead)

                            For Each id2 As ObjectId In btr1
                                Dim ent As Entity = trans.GetObject(id2, AutoCAD.DatabaseServices.OpenMode.ForRead)

                                If TypeOf ent Is BlockReference Then
                                    Dim br As BlockReference = CType(ent, BlockReference)


[Jeff H]

I guess you could check ownerId and not sure why I did this way but

Code - C#: [Select]

1.  
2.     public static IEnumerable<ObjectId> WhereOwnedBy(this ObjectIdCollection source, ObjectId ownerId)
3.         {
4.             if (source == null)
5.             {
6.                 throw new ArgumentNullException("source");
7.             }
8.             if (ownerId.IsNull)
9.             {
10.                 throw new ArgumentNullException("ownerId");
11.             }
12.             return WhereOwnedByImpl(source, ownerId);
13.         }
14.         private static IEnumerable<ObjectId> WhereOwnedByImpl(this ObjectIdCollection source, ObjectId ownerId)
15.         {
16.             TransactionManager tm = source[0].Database.TransactionManager;
17.             foreach (ObjectId item in source)
18.             {
19.                 DBObject dbo = tm.GetObject(item, OpenMode.ForRead, false, false);
20.                 if (dbo.OwnerId == ownerId)
21.                 {
22.                     yield return item;
23.                 }
24.             }
25.         }
26.         public static IEnumerable<ObjectId> WhereOwnedBy(this IEnumerable<ObjectId> source, ObjectId ownerId)
27.         {
28.             if (source == null)
29.             {
30.                 throw new ArgumentNullException("source");
31.             }
32.             if (ownerId.IsNull)
33.             {
34.                 throw new ArgumentNullException("ownerId");
35.             }
36.             return WhereOwnedByImpl(source, ownerId);
37.         }
38.  
39.         private static IEnumerable<ObjectId> WhereOwnedByImpl(this IEnumerable<ObjectId> source, ObjectId ownerId)
40.         {
41.             TransactionManager tm = source.First().Database.TransactionManager;
42.             foreach (ObjectId item in source)
43.             {
44.                 DBObject dbo = tm.GetObject(item, OpenMode.ForRead, false, false);
45.                 if (dbo.OwnerId == ownerId)
46.                 {
47.                     yield return item;
48.                 }
49.             }
50.         }
51.