退出时BeginQuit事件返回的Cancel不起效！

lihezhou

Imports AutoCAD
Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.EditorInput
Public Class BHNET
    Dim WithEvents QCADapp As AcadApplication
    Private Sub QCADapp_BeginQuit(ByRef Cancel As Boolean) Handles QCADapp.BeginQuit
        On Error Resume Next
        If MsgBox("AutoCAD即将退出，你确定退出吗？", vbYesNoCancel + vbQuestion, "Auto CAD") <> vbYes Then
            Cancel = True
        End If
    End Sub
    Public Sub New()
    End Sub
    Protected Overrides Sub Finalize()
        MyBase.Finalize()
    End Sub
    <CommandMethod("Show")>
    Public Sub Show()
        QCADapp = Autodesk.AutoCAD.ApplicationServices.Application.AcadApplication
    End Sub
End Class
这个代码怎么在CAD退出的时候，点击了NO不起效呢？如果是在CAD没有活动文档的时候点击NO是不会退出的。如果有文档的时候点击CAD关闭就会不起效！哪位大神用VB.net的。帮我看看

烟盒迷唇

发表的板块不对吧