假定已经在菜单编辑器中建立了窗体的弹出式菜单,其顶级菜单项的名称为a1,其“可见”属性为False。程序运行后,单击鼠标左键或右键都能弹出菜单的事件过程是()。
A. Private Sub Form_MouseDown(Button AS Intege, _Shift As Integer, X As Single, Y As Single) If Button=1 And Button=2 ThenP opupMenu a1 End If End Sub
B. Private Sub Form MouseDown(Button As Integeg_Shift As Integer, X As Single, Y As Single) PopupMenu a1 End Sub
C. Private Sub Form MouseDown(Button As Intege_Shift As Integeg, X As Single, Y As Single) If Button=1 Then PopupMenu a1 End If End Sub
D. Private Sub Form_MouseDown(Button As Integer, _Shift As Integer, X As Single, Y As Single)If Button=2 Then PopupMenu a1 End If End sub