<local:ButtonConverter x:Key="bc"/>
    
    <Style x:Key="LVButtonDir" TargetType="{x:Type Button}" BasedOn="{StaticResource LVButton}">
        <Setter Property="ToolTip" Value="Добавить в избранное"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="Button">
                    <Image Source="Resources/add2fav.png" Stretch="None"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
        <EventSetter Event="Button.Click" Handler="AddToFavorites"/>
        <Style.Triggers>
            <DataTrigger Binding="{Binding Path=Name, Converter={StaticResource bc}}" Value="True">
                <Setter Property="Visibility" Value="Hidden"/>
            </DataTrigger>
        </Style.Triggers>
    </Style>

    Public Sub AddToFavorites(sender As Object, e As RoutedEventArgs)
        Dim c As DirectoryEntry = CType(sender.DataContext, DirectoryEntry)
        Dim f As DirectoryEntry = g_ADData.CiscoIPPhoneDirectory.FirstOrDefault(Function(v) v.Name = c.Name)
        If f Is Nothing Then
            g_ADData.CiscoIPPhoneDirectory.Add(c)
            SaveData()
            CType(sender, Button).Visibility = Visibility.Hidden
        End If
    End Sub