WPFのComboBoxは、特定のアイテムを無効にします

<Grid Height="130" Width="316">
        <ComboBox Height="23" HorizontalAlignment="Left" Margin="78,12,0,0" Name="comboBox1" VerticalAlignment="Top" Width="120" 
                  ItemsSource="{Binding Items}" Background="Bisque" Foreground="Black"
                  SelectedIndex="0" >
  
            <!--Resource for Combobox to -->
            <ComboBox.Resources>
                <local:ComboboxDisableConverter x:Key="itemDisableconverter"/>
            </ComboBox.Resources>

            <!--ItemContainer Style for disabling Combobox Item-->
            <ComboBox.ItemContainerStyle>
                <Style TargetType="ComboBoxItem">
                    <Style.Triggers>
                        <DataTrigger Binding="{Bind