topic Get all entities inside a blockreference in .NET Forum

Get all entities inside a blockreference

哀家爆 — Sun, 21 Nov 2021 12:00:13 GMT

Hi, I've had some problems trying to get all entities inside a blockreference. As the following pic, there are 4 lines and another blockreference inside a blockreference.

var entities = new List<Entity>(); var objects = new DBObjectCollection(); block.Explode(objects);

the objects returns me only 4 lines but no blockreference.

What is amazing is that when I mirror the whole blockreference and execute the code again, I can get 4 lines and a blockreference from the mirrored blockreference.

Is there sth wrong with my code, or is there a better way to get all entities inside a blockreference.

Thanks.

Re: Get all entities inside a blockreference

_gile — Sun, 21 Nov 2021 12:12:55 GMT

Hi,

A block reference (BlockReference) does not contain entities, it is just a reference to a block definition (BlockTableRecord) which does contain entities.

You can get the ObjectId of the block definition using the BlockReference.BlockTableRecord property, open the BlockTablerecord for read and iterate through its contents.

Re: Get all entities inside a blockreference

哀家爆 — Sun, 21 Nov 2021 13:23:38 GMT

Thanks for your answer.

How am I supposed to understand that we can obtain the DBObjectCollection by using :

blockReference.Explode();

And I did get what I wanted by using the 'Explode()' method in most cases.

In the example above, the blockReference consists of four lines and another blockReference. In general, I can get what I want. Just this time I do not know what reason cause the 'Explode()' method to lose a blockReference.

Re: Get all entities inside a blockreference

hosneyalaa — Sun, 21 Nov 2021 14:42:34 GMT

Please look at this is

https://forums.autodesk.com/t5/net/how-to-get-poin-center-of-circle-in-block/m-p/10354555

Change this

id.ObjectClass.DxfName.ToUpper() == "CIRCLE")

id.ObjectClass.DxfName.ToUpper() == "line")

Re: Get all entities inside a blockreference

哀家爆 — Sun, 21 Nov 2021 15:27:03 GMT

Hi, _gile

var blockTableRecordId = block.BlockTableRecord; BlockTableRecord blockTableRecord = null; using (var ts = block.Database.TransactionManager.StartTransaction()) { blockTableRecord = ts.GetObject(blockTableRecordId, OpenMode.ForRead) as BlockTableRecord; foreach (var id in blockTableRecord) { var ent = (Entity)ts.GetObject(id, OpenMode.ForRead); ent.TransformBy(block.BlockTransform); entities.Add(ent); } }

Now I use your way to get all entities from a blockreference (throuth the blocktablerecord), and get the correct result.

But the following statement :

ent.TransformBy(block.BlockTransform);

throw a exception :

Autodesk.AutoCAD.Runtime.Exception:“eMissingSymbolTableRec”

What is wrong with this?

Best regards!~

Re: Get all entities inside a blockreference

哀家爆 — Sun, 21 Nov 2021 15:29:22 GMT

Hi, _gile

Now I use your way to get all entities from a blockreference (throuth the blocktablerecord), and get the correct result.

But the following statement :

ent.TransformBy(block.BlockTransform);

throw a exception : Autodesk.AutoCAD.Runtime.Exception:“eMissingSymbolTableRec”

What is wrong with this? Best regards!~

Re: Get all entities inside a blockreference

_gile — Sun, 21 Nov 2021 15:36:30 GMT

I was just trying to reply to your question : "is there a better way to get all entities inside a blockreference."

private static IEnumerable<Entity> GetEntitiesWithinBlock(BlockReference br) => ((BlockTableRecord)br.BlockTableRecord.GetObject(OpenMode.ForRead)) .Cast<ObjectId>() .Select(id => (Entity)id.GetObject(OpenMode.ForRead));

Re: Get all entities inside a blockreference

_gile — Sun, 21 Nov 2021 15:44:47 GMT

You should not tranform the entity within the block definition, you should clone it and transform the clone.

private static IEnumerable<Entity> GetEntitiesWithinBlock(BlockReference br) { var btr = (BlockTableRecord)br.BlockTableRecord.GetObject(OpenMode.ForRead); var ids = new ObjectIdCollection(btr.Cast<ObjectId>().ToArray()); var mapping = new IdMapping(); br.Database.DeepCloneObjects(ids, br.OwnerId, mapping, false); foreach (IdPair pair in mapping) { if (pair.IsCloned && pair.IsPrimary) { var entity = (Entity)pair.Value.GetObject(OpenMode.ForWrite); entity.TransformBy(br.BlockTransform); yield return entity; } } }

Re: Get all entities inside a blockreference

哀家爆 — Sun, 21 Nov 2021 15:49:15 GMT

thanks a lot，I will try again.

Re: Get all entities inside a blockreference

哀家爆 — Tue, 23 Nov 2021 07:43:08 GMT

What if I want to get all entities recursively?

public static void GetEntitiesWithinBlock(BlockReference br, Document doc, ref List<Entity> entities) { using (var ts = doc.Database.TransactionManager.StartTransaction()) { var btr = (BlockTableRecord)br.BlockTableRecord.GetObject(OpenMode.ForRead); var ids = new ObjectIdCollection(btr.Cast<ObjectId>().ToArray()); var mapping = new IdMapping(); br.Database.DeepCloneObjects(ids, br.OwnerId, mapping, false); var asd = br.BlockTransform; foreach (IdPair pair in mapping) { if (pair.IsCloned && pair.IsPrimary) { var entity = (Entity)ts.GetObject(pair.Value, OpenMode.ForWrite); if (entity is BlockReference blockReference) { GetEntitiesWithinBlock(blockReference, doc, ref entities); } else { entity.TransformBy(br.BlockTransform); entities.Add(entity); } } } } }

And the statement: entity.TransformBy(br.BlockTransform); throw a new exception: eCannotScaleNonUniformly.

Thanks a lot!

Re: Get all entities inside a blockreference

_gile — Tue, 23 Nov 2021 08:46:13 GMT

private static IEnumerable<Entity> GetEntitiesWithinBlock(BlockReference br) { var btr = (BlockTableRecord)br.BlockTableRecord.GetObject(OpenMode.ForRead); var ids = new ObjectIdCollection(btr.Cast<ObjectId>().ToArray()); var mapping = new IdMapping(); br.Database.DeepCloneObjects(ids, br.OwnerId, mapping, false); foreach (IdPair pair in mapping) { if (pair.IsCloned && pair.IsPrimary) { var entity = (Entity)pair.Value.GetObject(OpenMode.ForWrite); if (entity is BlockReference) { entity.TransformBy(br.BlockTransform); foreach (var ent in GetEntitiesWithinBlock((BlockReference)entity)) { yield return ent; } entity.Erase(); } else { entity.TransformBy(br.BlockTransform); yield return entity; } } } }

Re: Get all entities inside a blockreference

哀家爆 — Tue, 23 Nov 2021 09:13:35 GMT

When the entity is BlockReference,

entity.TransformBy(br.BlockTransform);

throw the exception: eMissingSymbolTableRec.

It seems that AutoCAD doesn't allow us to transform a blockReference which is within another blockReference .

Re: Get all entities inside a blockreference

_gile — Tue, 23 Nov 2021 09:41:01 GMT

@哀家爆 a écrit :

When the entity is BlockReference,
entity.TransformBy(br.BlockTransform);
throw the exception: eMissingSymbolTableRec.

It seems that AutoCAD doesn't allow us to transform a blockReference which is within another blockReference .

We do not transform the block reference which is within the block definition, we transform the clone.

The upper code works for me.

Re: Get all entities inside a blockreference

哀家爆 — Tue, 23 Nov 2021 09:47:34 GMT

Could you please help me to test the attached dwg file.

I've no idea why the exception happens in my test.

Thank you very much !

Re: Get all entities inside a blockreference

_gile — Tue, 23 Nov 2021 16:42:16 GMT

In the "blocktest"drawing, the block is not uniformy scaled.

Re: Get all entities inside a blockreference

NSJamieLiu — Tue, 07 May 2024 07:56:09 GMT

hi there: I am facing the same problem. I want to transform inner objects within a non uniformy scaled blockrefernce. So what should I do if the blockrefernce is not uniform scaled?

all the best