重新定义块 （.NET）

使用任何对象方法和属性来重新定义块。重新定义块时，图形中对该块的所有参照都会立即更新以反映新定义。Block

重新定义会影响块的先前和未来插入。常量属性将丢失，并被任何新的常量属性替换。即使新块没有属性，变量属性也保持不变。

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

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

                    ' Insert the block into the current space
                    Using acBlkRef As New BlockReference(New Point3d(0, 0, 0), acBlkTblRec.Id)

                        Dim acModelSpace As BlockTableRecord
                        acModelSpace = acTrans.GetObject(acCurDb.CurrentSpaceId, OpenMode.ForWrite)

                        acModelSpace.AppendEntity(acBlkRef)
                        acTrans.AddNewlyCreatedDBObject(acBlkRef, True)

                        MsgBox("CircleBlock has been created.")
                    End Using
                End Using
            End Using
        Else
            ' Redefine the block if it exists
            Dim acBlkTblRec As BlockTableRecord = _
                acTrans.GetObject(acBlkTbl.Item("CircleBlock"), OpenMode.ForWrite)

            ' Step through each object in the block table record
            For Each objID As ObjectId In acBlkTblRec

                Dim dbObj As DBObject = acTrans.GetObject(objID, OpenMode.ForRead)

                ' Revise the circle in the block
                If TypeOf dbObj Is Circle Then
                    Dim acCirc As Circle = dbObj

                    acTrans.GetObject(objID, OpenMode.ForWrite)
                    acCirc.Radius = acCirc.Radius * 2
                End If
            Next

            ' Update existing block references
            For Each objID As ObjectId In acBlkTblRec.GetBlockReferenceIds(False, True)
                Dim acBlkRef As BlockReference = acTrans.GetObject(objID, OpenMode.ForWrite)
                acBlkRef.RecordGraphicsModified(True)
            Next

            MsgBox("CircleBlock has been revised.")
        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("RedefiningABlock")]
public void RedefiningABlock()
{
    // 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);

                    // Insert the block into the current space
                    using (BlockReference acBlkRef = new BlockReference(new Point3d(0, 0, 0), acBlkTblRec.Id))
                    {
                        BlockTableRecord acModelSpace;
                        acModelSpace = acTrans.GetObject(acCurDb.CurrentSpaceId, OpenMode.ForWrite) as BlockTableRecord;

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

                        Application.ShowAlertDialog("CircleBlock has been created.");
                    }
                }
            }
        }
        else
        {
            // Redefine the block if it exists
            BlockTableRecord acBlkTblRec =
                acTrans.GetObject(acBlkTbl["CircleBlock"], OpenMode.ForWrite) as BlockTableRecord;

            // Step through each object in the block table record
            foreach (ObjectId objID in acBlkTblRec)
            {
                DBObject dbObj = acTrans.GetObject(objID, OpenMode.ForRead) as DBObject;

                // Revise the circle in the block
                if (dbObj is Circle)
                {
                    Circle acCirc = dbObj as Circle;

                    acTrans.GetObject(objID, OpenMode.ForWrite);
                    acCirc.Radius = acCirc.Radius * 2;
                }
            }

            // Update existing block references
            foreach (ObjectId objID in acBlkTblRec.GetBlockReferenceIds(false, true))
            {
                BlockReference acBlkRef = acTrans.GetObject(objID, OpenMode.ForWrite) as BlockReference;
                acBlkRef.RecordGraphicsModified(true);
            }

            Application.ShowAlertDialog("CircleBlock has been revised.");
        }

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

        // Dispose of the transaction
    }
}

Sub RedefiningABlock()
    ' Define the block
    Dim blockObj As AcadBlock
    Dim insertionPnt(0 To 2) As Double
    insertionPnt(0) = 0
    insertionPnt(1) = 0
    insertionPnt(2) = 0
    
    On Error Resume Next
    Set blockObj = Blocks("CircleBlock")
    Err.Clear
    
    If blockObj Is Nothing Then
        Set blockObj = ThisDrawing.Blocks.Add(insertionPnt, "CircleBlock")
        
        ' Add a circle to the block
        Dim circleObj As AcadCircle
        Dim center(0 To 2) As Double
        Dim radius As Double
        center(0) = 0
        center(1) = 0
        center(2) = 0
        rad = 2
        Set circleObj = blockObj.AddCircle(center, rad)

        ' Insert the block
        Dim blockRefObj As AcadBlockReference
        insertionPnt(0) = 0
        insertionPnt(1) = 0
        insertionPnt(2) = 0
        Set blockRefObj = ThisDrawing.ActiveLayout.Block.InsertBlock(insertionPnt, "CircleBlock", 1, 1, 1, 0)
    Else
        Set blockObj = ThisDrawing.Blocks.Item("CircleBlock")
        
        Dim acObj As AcadObject
        
        ' Redefine the circle objects in the block
        For Each acObj In blockObj
            If TypeOf acObj Is AcadCircle Then
                Dim acCirc As AcadCircle
                Set acCirc = acObj
                acCirc.radius = acCirc.radius * 2
            End If
        Next
        
        ' Update the blocks in the drawing
        Regen acAllViewports
    End If
End Sub