设已经在菜单编辑器中设计了窗体的快捷菜单,某顶级菜单为a1,且取消其“可见”属性。运行时,哪个事件
A.Private Sub Form_MouseDown(Button As Integer,Shift As Integer,X As Single,Y As Single) If Button=2 Then PopupMenu a1,2 End Sub
B.Private Sub Form_MouseDown(ButtonAsInteger,ShiftAsInteger,X As Single,Y As Single) PopupMenu a1,0 End Sub
C.Private Sub Form_Mouse Down(Button As Integer,Shift As Integer,X As Single,Y As Single) PopupMenu a1 End Sub
D.Private Sub Form_MouseDown(Button As Integer,Shift As Integer,X As Single,Y As Single) If(Button=vbLetfButton) Or (Button=vbRightButton) Then PopupMenu a1 End Sub