LB_ITEMFROMPOINT 信息， 细节如下：
1. API 的声明：
Const LB_ITEMFROMPOINT = &H1A9
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
注：如果以上的声明放在「一般模块」底下， 应在 Const 之前加上 Public 保留字， 并且将 Private 保留字去掉。

2. 调用例：(在表单上布置一个 TextBox 及一个 ListBox， 然后利用 MouseMove 事件程序来检测鼠标所在位置的选项)
Private Sub List1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
Dim pos As Long, idx As Long
pos = X / Screen.TwipsPerPixelX + Y / Screen.TwipsPerPixelY * 65536
idx = SendMessage(List1.hwnd, LB_ITEMFROMPOINT, 0, ByVal pos)
' idx 即等于鼠标所在位置的选项
If Idx < 65536 Then Text1.Text = List1.List(idx)
End Sub