VB.net solidworks 二次开发学习--报错

windows窗体应用程序：

Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim swapp As SldWorks.SldWorks
        Dim part As SldWorks.ModelDoc2
        Dim sketchmer As SldWorks.SketchManager
        swapp = CreateObject("sldworks.application")
        part = swapp.ActiveDoc
        sketchmer = part.SketchManager
        sketchmer.InsertSketch(True)
        sketchmer.CreateLine(-0.05, 0, 0, 0.05, 0, 0)
        sketchmer.CreateLine(-0.05, 0, 0, 0, 0.05 * 3 ^ 0.5, 0)
        sketchmer.CreateLine(0.05, 0, 0, 0, 0.05 * 3 ^ 0.5, 0)
        sketchmer.PerimeterCircle(0, 0.05 * 3 ^ 0.5, -0.05, 0, 0.05, 0)
        sketchmer.CreateCircle(0, 0.05 / 3 ^ (1 / 2), 0, 0.05, 0, 0)
        sketchmer.PerimeterCircle(0, 0, -0.025, 0.025 * 3 ^ (1 / 2), 0.025, 0.025 * 3 ^ (1 / 2))
        sketchmer.CreateCircleByRadius(0, 0.05 / 3 ^ (1 / 2), 0, 0.1)
        sketchmer.PerimeterCircle(0.1, 0, 0, 0.1, -0.1, 0)
        sketchmer.InsertSketch(True)
    End Sub
End Class
           

使用 sketchmer.PerimeterCircle时出现以下错误“遇到无效参数”（使用sketchmer.CreateCircle创建圆时正常）。没能解决

另 出现过“ sketchmer = part.SketchManager” 未将对象引用设置到对象的实例

，重启计算机后故障解除