selectonscreen方法求助

toosimple

以下是cad得帮助的一个例子，我把它放到了一个命令按钮的单击事件中，可是总提示出错，为什么阿

' This example adds objects to a selection set by prompting the user
    ' to select ones to add.
   
    ' Create the selection set
    Dim ssetObj As AcadSelectionSet
    Set ssetObj = ThisDrawing.SelectionSets.Add("TEST_SSET")
   
    ' Add objects to a selection set by prompting user to select on the screen
    ssetObj.SelectOnScreen
以下是出错时的帮助信息

AutoCAD main window is invisible. To turn on the window, set the visible property of the application object to acTrue.

雪山飞狐_lzh

me.hide

ssetObj.SelectOnScreen

me.show

toosimple

太感谢了