Edit Attribute Definitions (.NET)

You can use the Attribute object properties and methods to edit the attribute. Some of the properties on an attribute include the following:

FieldLength

Specifies the field length of the attribute

Height

Specifies the height of the attribute

HorizontalMode

Specifies the horizontal alignment of the attribute

IsMirroredInX

Specifies that the text of the attribute appears backwards

IsMirroredInY

Specifies that the text of the attribute appears upside-down

Position

Specifies the insertion point of the attribute

Prompt

Specifies the prompt string of the attribute

Rotation

Specifies the rotation of the attribute

Tag

Specifies the tag string of the attribute

TextString

Specifies the default value of the attribute

VerticalMode

Specifies the vertical alignment of the attribute

Redefine an attribute definition

This example creates a block and then adds an attribute to the block. The block is then inserted into the drawing. The attribute text is then updated to be displayed backward.

C# Example

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;

[CommandMethod("RedefiningAnAttribute")]
public void RedefiningAnAttribute()
{
    // Get the current database and start a transaction
    Database acCurDb;
    acCurDb = Application.DocumentManager.MdiActiveDocument.Database;

    using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
    {
        // Open the Block table for read
        BlockTable acBlkTbl;
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForRead) as BlockTable;

        ObjectId blkRecId = ObjectId.Null;

        if (!acBlkTbl.Has("CircleBlockWithAttributes"))
        {
            using (BlockTableRecord acBlkTblRec = new BlockTableRecord())
            {
                acBlkTblRec.Name = "CircleBlockWithAttributes";

                // Set the insertion point for the block
                acBlkTblRec.Origin = new Point3d(0, 0, 0);

                // Add a circle to the block
                using (Circle acCirc = new Circle())
                {
                    acCirc.Center = new Point3d(0, 0, 0);
                    acCirc.Radius = 2;

                    acBlkTblRec.AppendEntity(acCirc);

                    // Add an attribute definition to the block
                    using (AttributeDefinition acAttDef = new AttributeDefinition())
                    {
                        acAttDef.Position = new Point3d(0, 0, 0);
                        acAttDef.Prompt = "Door #: ";
                        acAttDef.Tag = "Door#";
                        acAttDef.TextString = "DXX";
                        acAttDef.Height = 1;
                        acAttDef.Justify = AttachmentPoint.MiddleCenter;
                        acBlkTblRec.AppendEntity(acAttDef);

                        acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForWrite);
                        acBlkTbl.Add(acBlkTblRec);
                        acTrans.AddNewlyCreatedDBObject(acBlkTblRec, true);
                    }
                }

                blkRecId = acBlkTblRec.Id;
            }
        }
        else
        {
            blkRecId = acBlkTbl["CircleBlockWithAttributes"];
        }

        // Create and insert the new block reference
        if (blkRecId != ObjectId.Null)
        {
            BlockTableRecord acBlkTblRec;
            acBlkTblRec = acTrans.GetObject(blkRecId, OpenMode.ForRead) as BlockTableRecord;

            using (BlockReference acBlkRef = new BlockReference(new Point3d(2, 2, 0), blkRecId))
            {
                BlockTableRecord acCurSpaceBlkTblRec;
                acCurSpaceBlkTblRec = acTrans.GetObject(acCurDb.CurrentSpaceId, OpenMode.ForWrite) as BlockTableRecord;

                acCurSpaceBlkTblRec.AppendEntity(acBlkRef);
                acTrans.AddNewlyCreatedDBObject(acBlkRef, true);

                // Verify block table record has attribute definitions associated with it
                if (acBlkTblRec.HasAttributeDefinitions)
                {
                    // Add attributes from the block table record
                    foreach (ObjectId objID in acBlkTblRec)
                    {
                        DBObject dbObj = acTrans.GetObject(objID, OpenMode.ForRead) as DBObject;

                        if (dbObj is AttributeDefinition)
                        {
                            AttributeDefinition acAtt = dbObj as AttributeDefinition;

                            if (!acAtt.Constant)
                            {
                                using (AttributeReference acAttRef = new AttributeReference())
                                {
                                    acAttRef.SetAttributeFromBlock(acAtt, acBlkRef.BlockTransform);
                                    acAttRef.Position = acAtt.Position.TransformBy(acBlkRef.BlockTransform);

                                    acAttRef.TextString = acAtt.TextString;

                                    acBlkRef.AttributeCollection.AppendAttribute(acAttRef);
                                    acTrans.AddNewlyCreatedDBObject(acAttRef, true);
                                }
                            }

                            // Change the attribute definition to be displayed as backwards
                            acTrans.GetObject(objID, OpenMode.ForWrite);
                            acAtt.IsMirroredInX = true;
                        }
                    }
                }
            }
        }

        // Save the new object to the database
        acTrans.Commit();

        // Dispose of the transaction
    }
}