ListViewItem Event Setter

Hi guys, I have an event setter set via a style as shown below, any ideas how I can write the HandleMouseEvent? I dont have a code behind... THanks

<ListView.ItemContainerStyle>

                <Style TargetType="{x:Type ListViewItem}">

                    <EventSetter Event='MouseEnter' Handler='HandleMouseEnter'/>

                </Style>

            </ListView.ItemContainerStyle>