<Window.Resources>
    <c:MyLogicConverter x:Key="LogicConverter" />
 
    <Style TargetType="{x:Type TextBox}" BasedOn="{StaticResource {x:Type TextBox}}" x:Key="MultiBound">
        <Setter Property="IsEnabled">
            <Setter.Value>
                <MultiBinding Converter="{StaticResource LogicConverter}">
                    <Binding ElementName="switch" Path="IsEnabled" />
                    <Binding ElementName="switch" Path="IsChecked" />
                </MultiBinding>
            </Setter.Value>
        </Setter>
    </Style>
</Window.Resources>
 
<StackPanel Orientation="Horizontal">
    <CheckBox Name="switch" />
    <TextBox Name="textBox2" Text="Test" Style="{StaticResource MultiBound}" />
</StackPanel>