ItemUnderMouse function returns the index

[nandagopal]

The ItemUnderMouse function returns the index of the item under the mouse. It uses the ClientToScreen API function to convert the (X, Y) coordinates of a point in the ListBox's coordinate system into screen coordinates. It then calls the LBItemFromPt API function to get the index of the item at that point.

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' Return the index of the item under the mouse.
Public Function ItemUnderMouse(ByVal list_hWnd As Long, _
    ByVal X As Single, ByVal Y As Single)
Dim pt As POINTAPI

    pt.X = X \ Screen.TwipsPerPixelX
    pt.Y = Y \ Screen.TwipsPerPixelY
    ClientToScreen list_hWnd, pt
    ItemUnderMouse = LBItemFromPt(list_hWnd, pt.X, pt.Y, _
        False)
End Function


The form's Load event handler initializes the array m_TooltipText, which holds tooltips for the items. It also contains a tooltip for item index -1 to use when the mouse is not over any item. You might want this tooltip to be blank but in this example it gives a generic "Select an item" prompt.

The ListBox's MouseMove event handler calls ItemUnderMouse to see what item is under the mouse and then sets the control's tooltip to that item's m_TooltipText value.


' See which item is under the mouse and display its tooltip.
Private Sub List1_MouseMove(Button As Integer, Shift As _
    Integer, X As Single, Y As Single)
    List1.ToolTipText = _
        m_TooltipText(ItemUnderMouse(List1.hwnd, X, Y))
End Sub