cad.net可以让某个要素居中显示 谁实现过？

''' 
    ''' 按对象进行缩放
    ''' 
    ''' 
    ''' 此数为正数，表示放大倍率（如果此数小于等于 0 则自动调整为1）
    ''' 
    Public Sub ZoomO(ByVal ID As ObjectId, Optional ByVal ZoomScale As Double = 1.0)
        Dim MinPt As Point3d = Nothing, MaxPt As Point3d = Nothing
        Using Trans As Transaction = DB.TransactionManager.StartTransaction
            Dim obj As DBObject = ID.GetObject(OpenMode.ForRead)
            If TypeOf obj Is Entity = False Then
                Trans.Commit()
                Exit Sub
            End If
            Dim Ent As Entity = obj
            MinPt = Ent.GeometricExtents.MinPoint : MaxPt = Ent.GeometricExtents.MaxPoint
            Trans.Commit()
        End Using
        Dim Ed As Editor = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument.Editor
        Dim VTabRec As New ViewTableRecord
        VTabRec.CenterPoint = New Point2d((MaxPt.X + MinPt.X) / 2.0, (MaxPt.Y + MinPt.Y) / 2.0)
        If ZoomScale <= 0 Then
            ZoomScale = 1.0
        End If
        VTabRec.Height = (MaxPt.Y - MinPt.Y) / ZoomScale
        Ed.SetCurrentView(VTabRec)
        Ed.UpdateScreen()
    End Sub