Создать собственный стиль. Вот пример, где цвет переднего плана изменяется на #F09609
<Style x:Key="ToggleSwitchButtonStyle"
TargetType="toolkitPrimitives:ToggleSwitchButton">
<Setter Property="Background" Value="{StaticResource PhoneBackgroundBrush}" />
<Setter Property="IsTabStop" Value="False" />
<Setter Property="SwitchForeground" Value="#F09609" /> <!-- CUSTOM VALUE -->
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="toolkitPrimitives:ToggleSwitchButton">
<Border x:Name="Root"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
CacheMode="BitmapCache"
Opacity="{TemplateBinding Opacity}"
Padding="{TemplateBinding Padding}">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal" />
<VisualState x:Name="Disabled">
<Storyboard>
<ColorAnimation Duration="0"
Storyboard.TargetName="SwitchBottom"
Storyboard.TargetProperty="(Grid.Background).(SolidColorBrush.Color)"
To="{StaticResource PhoneForegroundColor}" />
<ColorAnimation Duration="0"
Storyboard.TargetName="ThumbCenter"
Storyboard.TargetProperty="(Border.Background).(SolidColorBrush.Color)"
To="{StaticResource PhoneForegroundColor}" />
<DoubleAnimation Duration="0"
Storyboard.TargetName="Root"
Storyboard.TargetProperty="Opacity"
To="0.3" />
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="CheckStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0:0:0.05"
To="Unchecked" />
<VisualTransition GeneratedDuration="0:0:0.05"
To="Checked" />
</VisualStateGroup.Transitions>
<VisualState x:Name="Checked">
<Storyboard>
<DoubleAnimation Duration="0"
Storyboard.TargetName="BackgroundTranslation"
Storyboard.TargetProperty="(TranslateTransform.X)"
To="68">
<DoubleAnimation.EasingFunction>
<ExponentialEase EasingMode="EaseOut"
Exponent="15" />
</DoubleAnimation.EasingFunction>
</DoubleAnimation>
<DoubleAnimation Duration="0"
Storyboard.TargetName="ThumbTranslation"
Storyboard.TargetProperty="(TranslateTransform.X)"
To="68">
<DoubleAnimation.EasingFunction>
<ExponentialEase EasingMode="EaseOut"
Exponent="15" />
</DoubleAnimation.EasingFunction>
</DoubleAnimation>
</Storyboard>
</VisualState>
<VisualState x:Name="Dragging" />
<VisualState x:Name="Unchecked">
<Storyboard>
<DoubleAnimation Duration="0"
Storyboard.TargetName="BackgroundTranslation"
Storyboard.TargetProperty="(TranslateTransform.X)"
To="0" />
<DoubleAnimation Duration="0"
Storyboard.TargetName="ThumbTranslation"
Storyboard.TargetProperty="(TranslateTransform.X)"
To="0" />
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Grid x:Name="SwitchRoot"
Width="136"
Height="95"
Background="Transparent">
<Grid x:Name="SwitchTrack"
Width="88">
<Grid x:Name="SwitchBottom"
Height="32"
Background="{TemplateBinding SwitchForeground}">
<Rectangle x:Name="SwitchBackground"
Width="76"
Height="20"
HorizontalAlignment="Center"
VerticalAlignment="Center"
Fill="{TemplateBinding Background}">
<Rectangle.RenderTransform>
<TranslateTransform x:Name="BackgroundTranslation" />
</Rectangle.RenderTransform>
</Rectangle>
<Border BorderBrush="{StaticResource PhoneForegroundBrush}"
BorderThickness="2">
<Border BorderBrush="{StaticResource PhoneBackgroundBrush}"
BorderThickness="4" />
</Border>
</Grid>
<Border x:Name="SwitchThumb"
Width="28"
Height="36"
Margin="-4,0"
HorizontalAlignment="Left"
BorderBrush="{StaticResource PhoneBackgroundBrush}"
BorderThickness="4,0">
<Border.RenderTransform>
<TranslateTransform x:Name="ThumbTranslation" />
</Border.RenderTransform>
<Border x:Name="ThumbCenter"
Background="White"
BorderBrush="{StaticResource PhoneForegroundBrush}"
BorderThickness="2" />
</Border>
</Grid>
</Grid>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="ToggleSwitchStyle"
TargetType="toolkit:ToggleSwitch">
<Setter Property="Background" Value="{StaticResource PhoneBackgroundBrush}" />
<Setter Property="FontFamily" Value="{StaticResource PhoneFontFamilyLight}" />
<Setter Property="FontSize" Value="{StaticResource PhoneFontSizeLarge}" />
<Setter Property="Foreground" Value="{StaticResource PhoneForegroundBrush}" />
<Setter Property="IsTabStop" Value="False" />
<Setter Property="HorizontalContentAlignment" Value="Left" />
<Setter Property="SwitchForeground" Value="#F09609" /> <!-- CUSTOM VALUE -->
<Setter Property="VerticalContentAlignment" Value="Top" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="toolkit:ToggleSwitch">
<Border BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
CacheMode="BitmapCache"
Padding="{TemplateBinding Padding}">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal" />
<VisualState x:Name="Disabled">
<Storyboard>
<DoubleAnimation Duration="0"
Storyboard.TargetName="Header"
Storyboard.TargetProperty="Opacity"
To="0.3" />
<DoubleAnimation Duration="0"
Storyboard.TargetName="Content"
Storyboard.TargetProperty="Opacity"
To="0.3" />
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Grid Margin="12,5,36,42">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ContentControl x:Name="Header"
Margin="-1,0,0,0"
HorizontalAlignment="Left"
VerticalAlignment="Bottom"
Content="{TemplateBinding Header}"
ContentTemplate="{TemplateBinding HeaderTemplate}"
FontFamily="{StaticResource PhoneFontFamilyNormal}"
FontSize="{StaticResource PhoneFontSizeNormal}"
Foreground="{StaticResource PhoneBorderBrush}"
IsTabStop="False"
Opacity="{TemplateBinding Opacity}" />
<ContentControl x:Name="Content"
Grid.Row="1"
Margin="-1,1,0,-7"
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
Content="{TemplateBinding Content}"
ContentTemplate="{TemplateBinding ContentTemplate}"
IsTabStop="False"
Opacity="{TemplateBinding Opacity}" />
<toolkitPrimitives:ToggleSwitchButton x:Name="Switch"
Grid.RowSpan="2"
Grid.Column="1"
Margin="-22,-29,-24,-28"
VerticalAlignment="Bottom"
Background="{TemplateBinding Background}"
Opacity="{TemplateBinding Opacity}"
Style="{StaticResource ToggleSwitchButtonStyle}"
SwitchForeground="{TemplateBinding SwitchForeground}" />
</Grid>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>