You can use the Attribute object properties and methods to edit the attribute. Some of the properties on an attribute include the following:
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.
Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
<CommandMethod("RedefiningAnAttribute")> _
Public Sub RedefiningAnAttribute()
' Get the current database and start a transaction
Dim acCurDb As Autodesk.AutoCAD.DatabaseServices.Database
acCurDb = Application.DocumentManager.MdiActiveDocument.Database
Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()
' Open the Block table for read
Dim acBlkTbl As BlockTable
acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForRead)
Dim blkRecId As ObjectId = ObjectId.Null
If Not acBlkTbl.Has("CircleBlockWithAttributes") Then
Using acBlkTblRec As 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 acCirc As New Circle
acCirc.Center = New Point3d(0, 0, 0)
acCirc.Radius = 2
acBlkTblRec.AppendEntity(acCirc)
' Add an attribute definition to the block
Using acAttDef As 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)
acBlkTbl.UpgradeOpen()
acBlkTbl.Add(acBlkTblRec)
acTrans.AddNewlyCreatedDBObject(acBlkTblRec, True)
End Using
blkRecId = acBlkTblRec.Id
End Using
End Using
Else
blkRecId = acBlkTbl("CircleBlockWithAttributes")
End If
' Create and insert the new block reference
If blkRecId <> ObjectId.Null Then
Dim acBlkTblRec As BlockTableRecord
acBlkTblRec = acTrans.GetObject(blkRecId, OpenMode.ForRead)
Using acBlkRef As New BlockReference(New Point3d(2, 2, 0), acBlkTblRec.Id)
Dim acCurSpaceBlkTblRec As BlockTableRecord
acCurSpaceBlkTblRec = acTrans.GetObject(acCurDb.CurrentSpaceId, OpenMode.ForWrite)
acCurSpaceBlkTblRec.AppendEntity(acBlkRef)
acTrans.AddNewlyCreatedDBObject(acBlkRef, True)
' Verify block table record has attribute definitions associated with it
If acBlkTblRec.HasAttributeDefinitions Then
' Add attributes from the block table record
For Each objID As ObjectId In acBlkTblRec
Dim dbObj As DBObject = acTrans.GetObject(objID, OpenMode.ForRead)
If TypeOf dbObj Is AttributeDefinition Then
Dim acAtt As AttributeDefinition = dbObj
If Not acAtt.Constant Then
Using acAttRef As 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)
End Using
End If
' Change the attribute definition to be displayed as backwards
acAtt.UpgradeOpen()
acAtt.IsMirroredInX = True
End If
Next
End If
End Using
End If
' Save the new object to the database
acTrans.Commit()
' Dispose of the transaction
End Using
End Sub
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);
acBlkTbl.UpgradeOpen();
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
acAtt.UpgradeOpen();
acAtt.IsMirroredInX = true;
}
}
}
}
}
// Save the new object to the database
acTrans.Commit();
// Dispose of the transaction
}
}
Sub RedefiningAnAttribute()
' Define the block
Dim blockObj As AcadBlock
Dim insertionPnt(0 To 2) As Double
insertionPnt(0) = 0
insertionPnt(1) = 0
insertionPnt(2) = 0
Set blockObj = ThisDrawing.Blocks.Add(insertionPnt, "CircleBlockWithAttributes")
' Add an attribute to the block
Dim attributeObj As AcadAttribute
Dim height As Double
Dim mode As Long
Dim prompt As String
Dim insertionPoint(0 To 2) As Double
Dim tag As String
Dim value As String
height = 1
mode = acAttributeModeVerify
prompt = "Door #: "
insertionPoint(0) = 0
insertionPoint(1) = 0
insertionPoint(2) = 0
tag = "Door#"
value = "DXX"
Set attributeObj = blockObj.AddAttribute(height, mode, prompt, insertionPoint, tag, value)
' Insert the block, creating a block reference
' and an attribute reference
Dim blockRefObj As AcadBlockReference
insertionPnt(0) = 2
insertionPnt(1) = 2
insertionPnt(2) = 0
Set blockRefObj = ThisDrawing.ActiveLayout.Block.InsertBlock(insertionPnt, "CircleBlockWithAttributes", 1, 1, 1, 0)
' Redefine the attribute text to display backwards.
attributeObj.Backward = True
attributeObj.Update
End Sub