程序代码：

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
Private Const LB_ITEMFROMPOINT = &H1A9

Private Function ShowListTips(ByRef objList As Control, Button As Integer, Shift As Integer, X As Single, Y As Single) As Long

    On Error GoTo errHandler

    '//! 支持dirListBox、FileListBox，ListBox
    Dim lXPoint As Long, lYPoint As Long
    Dim lIndex  As Long, n As Long

    If Button = 0 Then 'if no button was pressed
        lXPoint = CLng(X / Screen.TwipsPerPixelX)
        lYPoint = CLng(Y / Screen.TwipsPerPixelY)

        With objList
            'get selected item from list
            lIndex = SendMessage(.hwnd, LB_ITEMFROMPOINT, 0, ByVal ((lYPoint * 65536) + lXPoint))

            'get the hidden item count if the objList is a dirListbox
            'If TypeOf objList Is DirListBox Then
            If TypeName(objList) = "DirListBox" Then
                n = UBound(Split(objList.List(0), "\"))
            End If

            'show tip or clear last one
            If (lIndex >= 0) And (lIndex <= .ListCount+n) Then
                .ToolTipText = .List(lIndex-n)
            Else
                .ToolTipText = ""
            End If

        End With

    End If

    Exit Function

errHandler:
    Debug.Print Err.Number, Err.Description
End Function
'调用示例：
'在ListBox的MouseMove事件中 
'Call ShowListTips(控件名称，Button,Shift,X,Y)