Change the Color of Attribute Definition using C#

[ilovejingle]

I have a block in the drawing which contains an attribute whoes tag is "24GENPOS", What I want to do is to change the layer and color of that specific attribute definition, I am starting with the color first, The program can correctly locate the block and execute the code, however the color is not changed.

        public void cmdATTLAY()
        {
            var attName = "24GENPOS";
            Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;
            Database db = HostApplicationServices.WorkingDatabase;
            ObjectId blkTabId = db.BlockTableId;
            using (Transaction trans = db.TransactionManager.StartTransaction())
            {
                try
                {
                    BlockTable blkTab = trans.GetObject(blkTabId, OpenMode.ForRead) as BlockTable;
                    foreach(ObjectId blkTabRecId in blkTab)
                    {
                        bgFunction.ChangeAttLayer(blkTabRecId, attName, "something");
                    }
                }
                catch(Autodesk.AutoCAD.Runtime.Exception ex)
                {
                    ed.WriteMessage("Error : " + ex.Message);
                }
            }
        }

        public static void ChangeAttLayer(ObjectId blockId,string attName, string layerName)
        {
            using (Transaction trans = HostApplicationServices.WorkingDatabase.TransactionManager.StartTransaction())
            {
                BlockTableRecord blkTabRec = trans.GetObject(blockId, OpenMode.ForRead) as BlockTableRecord;
                foreach (ObjectId objId in blkTabRec)
                {
                    DBObject objDb = trans.GetObject(objId, OpenMode.ForWrite);
                    if (objDb is AttributeDefinition)
                    {
                        var attDef = (AttributeDefinition)objDb;
                        if (attDef.Tag == attName)
                        {
                            attDef.ColorIndex = 1;
                        }
                    }
                }
                trans.Commit();
            }

        }

[Alexander.Rivilis · Accepted solution]

@ilovejingle 

You have to add trans.Commit() in method cmdATTLAY()

P.S.: If drawing has block references (BlockReference) with this attribute, changing color of attribute definitions do not change color of attribute references

[ilovejingle]

opps, silly mistake of mine. Thank you very much. Do you have how to sync all the attribute references?

[Alexander.Rivilis]

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@ilovejingle wrote:

opps, silly mistake of mine. Thank you very much. Do you have how to sync all the attribute references?

---

There are several ways:

1. Start command _ATTSYNC with Editor.Command or Editor.CommandAsync

2. Iterate all block references (BlockReference) in Database (not only in Model Space, but in all BlockTableRecord's), find all attribute (AttributeReference) with your's Tag and change color.