Semi.Avalonia/demo/Semi.Avalonia.Demo/Themes/ToggleSwitch.axaml

<ResourceDictionary xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <ControlTheme x:Key="ThemeToggleSwitch"
                  BasedOn="{StaticResource ButtonToggleSwitch}"
                  TargetType="ToggleSwitch">
        <Setter Property="Padding" Value="8" />
        <Setter Property="OnContentTemplate">
            <DataTemplate>
                <PathIcon Theme="{StaticResource InnerPathIcon}" Data="{Binding}" />
            </DataTemplate>
        </Setter>
        <Setter Property="OffContentTemplate">
            <DataTemplate>
                <PathIcon Theme="{StaticResource InnerPathIcon}" Data="{Binding}" />
            </DataTemplate>
        </Setter>
        <Setter Property="ContentTemplate">
            <DataTemplate>
                <PathIcon Theme="{StaticResource InnerPathIcon}" Data="{Binding}" />
            </DataTemplate>
        </Setter>
    </ControlTheme>

    <ControlTheme x:Key="SplitViewToggleSwitch"
                  BasedOn="{StaticResource ThemeToggleSwitch}"
                  TargetType="ToggleSwitch">
        <Setter Property="Content"
                Value="M5 2H19C20.6569 2 22 3.34315 22 5V19C22 20.6569 20.6569 22 19 22H5C3.34315 22 2 20.6569 2 19V5C2 3.34315 3.34315 2 5 2ZM6 4C5.44772 4 5 4.44772 5 5V19C5 19.5523 5.44772 20 6 20H9C9.55229 20 10 19.5523 10 19V5C10 4.44772 9.55229 4 9 4H6Z" />
    </ControlTheme>
</ResourceDictionary>