VB中添加圆的标注？

Sub Example_AddDimDiametric()    ' 该示例在模型空间中创建直径标注。        Dim dimObj As AcadDimDiametric    Dim chordPoint(0 To 2) As Double    Dim farChordPoint(0 To 2) As Double    Dim leaderLength As Double        ' 定义标注    chordPoint(0) = 5#: chordPoint(1) = 3#: chordPoint(2) = 0#    farChordPoint(0) = 5#: farChordPoint(1) = 5#: farChordPoint(2) = 0#    leaderLength = 1#        ' 在模型空间中创建直径标注    Set dimObj = ThisDrawing.ModelSpace.AddDimDiametric(chordPoint, farChordPoint, leaderLength)    ZoomAll    End Sub