vbnet 在autocad当中Dim stepRectangleId As ObjectId = dbAddToModelSpacestepRectangle

在AutoCAD中，使用VB.NET语言编写的代码可以将一个矩形对象添加到模型空间中。以下是一个示例代码：

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

Public Class MyCommands
    <CommandMethod("AddRectangle")>
    Public Sub AddRectangle()
        Dim doc As Document = Application.DocumentManager.MdiActiveDocument
        Dim db As Database = doc.Database
        Dim ed As Editor = doc.Editor

        Using trans As Transaction = db.TransactionManager.StartTransaction()
            Dim ms As BlockTableRecord = CType(trans.GetObject(SymbolUtilityServices.GetBlockModelSpaceId(db), OpenMode.ForWrite), BlockTableRecord)

            ' 创建矩形
            Dim startPoint As New Point3d(0, 0, 0)
            Dim endPoint As New Point3d(100, 100, 0)
            Dim stepRectangle As New Rectangle(startPoint, endPoint)
            
            ' 将矩形添加到模型空间中
            Dim stepRectangleId As ObjectId = ms.AppendEntity(stepRectangle)
            trans.AddNewlyCreatedDBObject(stepRectangle, True)
            
            trans.Commit()
        End Using
    End Sub
End Class

在上述代码中，我们首先获取当前活动文档、数据库和编辑器对象。然后，在使用事务进行数据库操作时，我们获取模型空间的块表记录对象。接下来，我们创建一个矩形对象，并将其添加到模型空间中。最后，我们提交事务以保存更改。