The framework calls this member function to inform the owner of an owner-draw list box or combo box that the list box or combo box is destroyed or that items have been removed by CComboBox::DeleteString, CListBox::DeleteString, CComboBox::ResetContent, or CListBox::ResetContent.
If the hwndItem member of the DELETEITEMSTRUCT structure belongs to a combo box or list box, then the DeleteItem virtual function of the appropriate class is called. Override the DeleteItem member function of the appropriate control's class to delete item-specific data.
This member function is called by the framework to allow your application to handle a Windows message. The parameters passed to your function reflect the parameters received by the framework when the message was received. If you call the base-class implementation of this function, that implementation will use the parameters originally passed with the message and not the parameters you supply to the function.