当点击向上移按钮时，被选中的item向上移动一位，被选中的item的上一个item向下一位
当点击向下移按钮时，被选中的item向下移动一位，被选中的item的下一个item向上一位
private sub form_load()
listbox1.additem "a"
listbox1.additem "b"
listbox1.additem "c"
listbox1.additem "d"
command1.caption="向上移"
command2.caption="向下移"
end sub
private sub command1_click()
end sub
private sub command2_click()
end sub
LAOD事件中，你写错了一些内容
给你具体代码，你直接用即可：
Private Sub Command1_Click()
If List1.ListIndex > 0 Then
List1.ListIndex = List1.ListIndex - 1
Else
List1.ListIndex = List1.ListCount - 1
End If
End Sub
Private Sub Command2_Click()
If List1.ListIndex >= List1.ListCount - 1 Then
List1.ListIndex = 0
Else
List1.ListIndex = List1.ListIndex + 1
End If
End Sub
Private Sub form_load()
List1.AddItem "a"
List1.AddItem "b"
List1.AddItem "c"
List1.AddItem "d"
Command1.Caption = "向上移"
Command2.Caption = "向下移"
End Sub