Define Blocks (.NET)

To create a new block, create a new BlockTableRecord object and use the Add method to append it to the BlockTable object. Once you create a BlockTableRecord object, use the Name property to assign a name to the block and the objects to be displayed when the block is inserted into the drawing with the AppendEntity method.

You then add any geometrical object, or another block, to the newly created BlockTableRecord object. Objects are added to the BlockTableRecord object with the AppendEntity method. You can then insert an instance of the block into the drawing by creating a new BlockReference object and appending it to model space or the BlockTableRecord object that is associated with a Layout object. An inserted block is an object called a block reference.

You can also create a block by using the WBlock method to write objects out to a separate drawing file. The drawing file can then be used as a block definition for other drawings. AutoCAD considers any drawing you insert into another drawing to be a block.

For more information on defining blocks, see “About Defining Blocks” in the product Help system.

Define a block

This example defines a block and adds a circle to the block definition. It then inserts the block into the drawing as a block reference.

C#

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

[CommandMethod("CreatingABlock")]
public void CreatingABlock()
{
    // 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;

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

                // 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);

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

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

        // Dispose of the transaction
    }
}

VB.NET

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry

<CommandMethod("CreatingABlock")> _
Public Sub CreatingABlock()
    ' 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)

        If Not acBlkTbl.Has("CircleBlock") Then
            Using acBlkTblRec As New BlockTableRecord
                acBlkTblRec.Name = "CircleBlock"

                ' 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)

                    acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForWrite)
                    acBlkTbl.Add(acBlkTblRec)
                    acTrans.AddNewlyCreatedDBObject(acBlkTblRec, True)
                End Using
            End Using
        End If

        ' Save the new object to the database
        acTrans.Commit()

        ' Dispose of the transaction
    End Using
End Sub

VBA/ActiveX Code Reference

Sub CreatingABlock()
    ' 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, "CircleBlock")

    ' Add a circle to the block
    Dim center(0 To 2) As Double
    Dim radius As Double
    center(0) = 0
    center(1) = 0
    center(2) = 0
    rad = 2
    blockObj.AddCircle(center, rad)
End Sub