Silverlight DataTrigger is the Answer to View Model / MVVM Issues

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation" xmlns:uriMapper="clr-namespace:System.Windows.Navigation;assembly=System.Windows.Controls.Navigation" xmlns:System="clr-namespace:System;assembly=mscorlib" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d">

    <ResourceDictionary.MergedDictionaries>
        <ResourceDictionary Source="Brushes.xaml" />
        <ResourceDictionary Source="Fonts.xaml" />
        <ResourceDictionary Source="CoreStyles.xaml" />
    </ResourceDictionary.MergedDictionaries>

    <!--
    ***************************************************************************
    A note about the width of the navigation app: this theme is designed to 
    max out at 960px. That keeps the content at a reasonable width on really
    big screens, but if you'd like to change it, it's easy to do! Just change
    the value of ContentMaxWidth (below). Or if you don't want a maxium width
    for the content, then just delete the lines where it shows up.
    ***************************************************************************
    -->

    <System:Double x:Key="ContentMaxWidth">960</System:Double>

    <!--
    ***************************************************************************
    Main Page Styles
    ***************************************************************************
    -->

    <!--LayoutRootGridStyle-->
    <Style x:Key="BackgroundBorderStyle" TargetType="Border">
        <Setter Property="Background">
            <Setter.Value>
                <LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
                    <GradientStop Offset="0" Color="#30FFFFFF" />
                    <GradientStop Offset="0.5" Color="#00FFFFFF" />
                </LinearGradientBrush>        
            </Setter.Value>
        </Setter>
        <Setter Property="BorderBrush">
            <Setter.Value>
                <LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
                    <GradientStop Offset="0" Color="#30000000" />
                    <GradientStop Offset="0.5" Color="#00000000" />
                </LinearGradientBrush>
            </Setter.Value>
        </Setter>
        <Setter Property="MaxWidth" Value="{StaticResource ContentMaxWidth}" />
        <Setter Property="BorderThickness" Value="1,0" />
    </Style>

    <!--LayoutRootGridStyle-->
    <Style x:Key="LayoutRootGridStyle" TargetType="Grid">
        <Setter Property="MaxWidth" Value="{StaticResource ContentMaxWidth}" />
        <Setter Property="HorizontalAlignment" Value="Stretch" />
        <Setter Property="Margin" Value="46,0" />
        <Setter Property="VerticalAlignment" Value="Top" />
    </Style>

    <!--ContentBorderStyle-->
    <Style x:Key="ContentBorderStyle" TargetType="Border">
        <Setter Property="Background" Value="{x:Null}" />
        <Setter Property="BorderBrush" Value="{x:Null}" />
        <Setter Property="BorderThickness" Value="0,0,0,0" />
        <Setter Property="Margin" Value="0,0,0,0" />
        <Setter Property="VerticalAlignment" Value="Stretch" />
        <Setter Property="HorizontalAlignment" Value="Stretch" />
    </Style>

    <!--ContentFrameStyle-->
    <Style x:Key="ContentFrameStyle" TargetType="navigation:Frame">
        <Setter Property="Background" Value="Transparent" />
        <Setter Property="BorderBrush" Value="Transparent" />
        <Setter Property="Padding" Value="30,0" />
        <Setter Property="VerticalContentAlignment" Value="Stretch" />
        <Setter Property="HorizontalContentAlignment" Value="Stretch" />
    </Style>

    <!--NavigationGridStyle-->
    <Style x:Key="NavigationGridStyle" TargetType="Grid">
        <Setter Property="Background" Value="Transparent" />
        <Setter Property="Height" Value="87" />
        <Setter Property="Margin" Value="30,0" />
        <Setter Property="VerticalAlignment" Value="Top" />
    </Style>

    <!--BrandingBorderStyle-->
    <Style x:Key="BrandingBorderStyle" TargetType="Border">
        <Setter Property="Height" Value="46" />
        <Setter Property="Margin" Value="30,0" />
        <Setter Property="VerticalAlignment" Value="Top" />
        <Setter Property="HorizontalAlignment" Value="Left" />
        <Setter Property="Padding" Value="0,5,0,0" />
    </Style>

    <!--BrandingStackPanelStyle-->
    <Style x:Key="BrandingStackPanelStyle" TargetType="StackPanel">
        <Setter Property="HorizontalAlignment" Value="Stretch" />
        <Setter Property="Orientation" Value="Vertical" />
    </Style>

    <!--LogoIcon-->
    <Style x:Key="LogoIcon" TargetType="ContentControl">
        <Setter Property="Content" Value="lorem ipsum dolor sit" />
        <Setter Property="Foreground" Value="{StaticResource NavigationForegroundColorBrush}" />
        <Setter Property="Height" Value="24" />
        <Setter Property="Margin" Value="0" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ContentControl">
                    <Grid Margin="0,5,0,0">
                        <TextBlock Style="{StaticResource HeaderTextStyle}" Text="{TemplateBinding Content}" Foreground="{TemplateBinding Foreground}" FontWeight="Normal" FontSize="{TemplateBinding FontSize}" Margin="10,4,0,0" VerticalAlignment="Center" Padding="0" />
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <!--ApplicationNameStyle-->
    <Style x:Key="ApplicationNameStyle" TargetType="TextBlock">
        <Setter Property="Foreground" Value="{StaticResource NavigationForegroundColorBrush}" />
        <Setter Property="FontFamily" Value="{StaticResource HeadingFontFamily}" />
        <Setter Property="FontSize" Value="{StaticResource Heading3FontSize}" />
        <Setter Property="FontWeight" Value="Bold" />
        <Setter Property="TextOptions.TextHintingMode" Value="Animated" />
        <Setter Property="Opacity" Value="0.5" />
        <Setter Property="Margin" Value="30,17,0,0" />
        <Setter Property="VerticalAlignment" Value="Center" />
        <Setter Property="HorizontalAlignment" Value="Left" />
    </Style>

    <!--LinksBorderStyle-->
    <Style x:Key="LinksBorderStyle" TargetType="Border">
        <Setter Property="Background" Value="{StaticResource StaticControlBackground}" />
        <Setter Property="Effect" Value="{StaticResource ControlShadowEffect}" />
        <Setter Property="Height" Value="38" />
        <Setter Property="Margin" Value="0" />
        <Setter Property="HorizontalAlignment" Value="Stretch" />
        <Setter Property="VerticalAlignment" Value="Top" />
    </Style>

    <!--LinksStackPanelStyle-->
    <Style x:Key="LinksStackPanelStyle" TargetType="StackPanel">
        <Setter Property="VerticalAlignment" Value="Stretch" />
        <Setter Property="HorizontalAlignment" Value="Left" />
        <Setter Property="Orientation" Value="Horizontal" />
        <Setter Property="Height" Value="47" />
        <Setter Property="Margin" Value="0,0,0,0" />
    </Style>

    <!--LinkStyle-->
    <Style x:Key="LinkStyle" TargetType="HyperlinkButton">
        <Setter Property="BorderThickness" Value="1" />
        <Setter Property="Background" Value="{StaticResource InputSelectionBrush}" />
        <Setter Property="BorderBrush" Value="{x:Null}" />
        <Setter Property="Foreground" Value="{StaticResource NavigationInactiveForegroundColorBrush}" />
        <Setter Property="FontFamily" Value="{StaticResource ContentFontFamily}" />
        <Setter Property="FontSize" Value="{StaticResource Heading5FontSize}" />
        <Setter Property="FontWeight" Value="Bold" />
        <Setter Property="TextOptions.TextHintingMode" Value="Animated" />
        <Setter Property="Cursor" Value="Hand" />
        <Setter Property="Height" Value="47" />
        <Setter Property="VerticalContentAlignment" Value="Center" />
        <Setter Property="HorizontalContentAlignment" Value="Center" />
        <Setter Property="Padding" Value="24,4" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="HyperlinkButton">
                    <Grid x:Name="ButtonGrid" Cursor="{TemplateBinding Cursor}">
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Normal" />
                                <VisualState x:Name="MouseOver">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="InteractiveElementBorder" Storyboard.TargetProperty="(UIElement.Visibility)">
                                            <DiscreteObjectKeyFrame KeyTime="00:00:00">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="InteractiveElementBorder" Storyboard.TargetProperty="(UIElement.Opacity)">
                                            <EasingDoubleKeyFrame KeyTime="00:00:00" Value="0.95" />
                                        </DoubleAnimationUsingKeyFrames>
                                        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="InteractiveBorder" Storyboard.TargetProperty="(UIElement.Opacity)">
                                            <EasingDoubleKeyFrame KeyTime="00:00:00" Value="1" />
                                        </DoubleAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Pressed">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="InteractiveElementBorder" Storyboard.TargetProperty="(UIElement.Visibility)">
                                            <DiscreteObjectKeyFrame KeyTime="00:00:00">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="InteractiveElementBorder" Storyboard.TargetProperty="(UIElement.Opacity)">
                                            <EasingDoubleKeyFrame KeyTime="00:00:00" Value="0.8" />
                                        </DoubleAnimationUsingKeyFrames>
                                        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="InteractiveBorder" Storyboard.TargetProperty="(UIElement.Opacity)">
                                            <EasingDoubleKeyFrame KeyTime="00:00:00" Value="1" />
                                        </DoubleAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Duration="0" Storyboard.TargetName="DisabledOverlay" Storyboard.TargetProperty="Visibility">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="(FrameworkElement.VerticalAlignment)">
                                            <DiscreteObjectKeyFrame KeyTime="00:00:00">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <VerticalAlignment>Center</VerticalAlignment>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="DisabledOverlay" Storyboard.TargetProperty="(FrameworkElement.HorizontalAlignment)">
                                            <DiscreteObjectKeyFrame KeyTime="00:00:00">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <HorizontalAlignment>Center</HorizontalAlignment>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="DisabledOverlay" Storyboard.TargetProperty="(FrameworkElement.VerticalAlignment)">
                                            <DiscreteObjectKeyFrame KeyTime="00:00:00">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <VerticalAlignment>Center</VerticalAlignment>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="DisabledOverlay" Storyboard.TargetProperty="(UIElement.Opacity)">
                                            <EasingDoubleKeyFrame KeyTime="00:00:00" Value="0.5" />
                                        </DoubleAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                            <VisualStateGroup x:Name="LinkStates">
                                <VisualState x:Name="ActiveLink">
                                    <Storyboard>
                                        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="ActiveBorder" Storyboard.TargetProperty="(UIElement.Opacity)">
                                            <EasingDoubleKeyFrame KeyTime="00:00:00" Value="1" />
                                        </DoubleAnimationUsingKeyFrames>
                                        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="ContentBorder" Storyboard.TargetProperty="(UIElement.Opacity)">
                                            <EasingDoubleKeyFrame KeyTime="00:00:00" Value="1" />
                                        </DoubleAnimationUsingKeyFrames>
                                        <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="Indicator" d:IsOptimized="True" />
                                        <ColorAnimation To="{StaticResource NavigationActiveForegroundColor}" BeginTime="00:00:00" Duration="00:00:00" Storyboard.TargetName="ContentPresenter" Storyboard.TargetProperty="(UIElement.Foreground).(SolidColorBrush.Color)" />
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="InactiveLink" />
                            </VisualStateGroup>
                            <VisualStateGroup x:Name="FocusStates">
                                <VisualState x:Name="Focused">
                                    <Storyboard>
                                        <DoubleAnimationUsingKeyFrames Storyboard.TargetName="FocusVisualElement" Storyboard.TargetProperty="Opacity">
                                            <SplineDoubleKeyFrame KeyTime="0" Value="0.35" />
                                        </DoubleAnimationUsingKeyFrames>
                                        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="FocusVisualElement" Storyboard.TargetProperty="(Rectangle.RadiusX)">
                                            <EasingDoubleKeyFrame KeyTime="00:00:00" Value="1" />
                                        </DoubleAnimationUsingKeyFrames>
                                        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="FocusVisualElement" Storyboard.TargetProperty="(Rectangle.RadiusY)">
                                            <EasingDoubleKeyFrame KeyTime="00:00:00" Value="1" />
                                        </DoubleAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Unfocused" />
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Path x:Name="Indicator" Width="15" Height="9" Stretch="Fill" Data="M0,0 L1,0 L0.5,1 Z" Fill="{StaticResource ColorAccentSolidBrush}" VerticalAlignment="Bottom" Margin="0,0,0,0" Effect="{StaticResource ControlShadowEffect}" Opacity="0" />
                        <Grid Margin="0,0,0,9">
                            <Rectangle x:Name="FocusVisualElement" Stroke="{TemplateBinding BorderBrush}" StrokeThickness="2" Opacity="0" Margin="-1" RadiusX="1" RadiusY="1" />
                            <Border x:Name="InteractiveBorder" MinWidth="{TemplateBinding MinWidth}" MinHeight="{TemplateBinding MinHeight}" Background="{StaticResource StaticControlBackgroundOver}" Opacity="0" />
                            <Border x:Name="InteractiveElementBorder" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Visibility="Collapsed" />
                            <Border x:Name="ActiveBorder" MinWidth="{TemplateBinding MinWidth}" MinHeight="{TemplateBinding MinHeight}" Background="{StaticResource InputSelectionBrush}" Opacity="0" />
                            <TextBlock x:Name="DisabledOverlay" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Margin="{TemplateBinding Padding}" Text="{TemplateBinding Content}" Foreground="Purple" Visibility="Collapsed" />
                            <Border x:Name="ContentBorder" MinWidth="{TemplateBinding MinWidth}" MinHeight="{TemplateBinding MinHeight}" Opacity="1" BorderBrush="Transparent" BorderThickness="0.5,0" />
                            <ContentControl x:Name="ContentPresenter" FontWeight="{TemplateBinding FontWeight}" Foreground="{TemplateBinding Foreground}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Margin="{TemplateBinding Padding}" Content="{TemplateBinding Content}" ContentTemplate="{TemplateBinding ContentTemplate}" Opacity="1" />
                        </Grid>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <!--DividerStyle-->
    <Style x:Key="DividerStyle" TargetType="Rectangle">
        <Setter Property="Visibility" Value="Collapsed" />
    </Style>

    <!--
    ***************************************************************************
    Style Updates for Nav Template
    ***************************************************************************
    -->

    <!--NavBrandingStackPanelStyle-->
    <Style x:Key="NavBrandingStackPanelStyle" TargetType="StackPanel">
        <Setter Property="HorizontalAlignment" Value="Stretch" />
        <Setter Property="Orientation" Value="Horizontal" />
    </Style>

    <!--LogoIcon-->
    <Style x:Key="NavLogoIcon" TargetType="ContentControl" BasedOn="{StaticResource LogoIcon}">
        <Setter Property="FontSize" Value="12" />
        <Setter Property="Foreground" Value="{StaticResource NavigationInactiveForegroundColorBrush}" />
        <Setter Property="Margin" Value="8,0,0,2" />
    </Style>

    <!--NavContentBorderStyle-->
    <Style x:Key="NavContentBorderStyle" TargetType="Border" BasedOn="{StaticResource ContentBorderStyle}">
        <Setter Property="Margin" Value="0" />
    </Style>

    <!--NavContentFrameStyle-->
    <Style x:Key="NavContentFrameStyle" TargetType="navigation:Frame" BasedOn="{StaticResource ContentFrameStyle}">
        <Setter Property="UriMapper">
            <Setter.Value>
                <uriMapper:UriMapper>
                    <uriMapper:UriMapping MappedUri="/Views/Home.xaml" Uri="" />
                    <uriMapper:UriMapping MappedUri="/Views/{pageName}.xaml" Uri="/{pageName}" />
                    <uriMapper:UriMapping MappedUri="/Views/{pageName}.xaml" Uri="{}{pageName}" />
                </uriMapper:UriMapper>
            </Setter.Value>
        </Setter>
    </Style>

    <!--NavBrandingBorderStyle-->
    <Style x:Key="NavBrandingBorderStyle" TargetType="Border">
        <Setter Property="Margin" Value="0" />
        <Setter Property="VerticalAlignment" Value="Top" />
        <Setter Property="HorizontalAlignment" Value="Left" />
        <Setter Property="Padding" Value="0,5,0,0" />
    </Style>

    <!--NavLinksBorderStyle-->
    <Style x:Key="NavLinksBorderStyle" TargetType="Border" BasedOn="{StaticResource LinksBorderStyle}">
        <Setter Property="Margin" Value="0" />
    </Style>

    <!--
    ***************************************************************************
    Content Page Styles
    ***************************************************************************
    -->

    <!--PageStyle-->
    <Style x:Key="PageStyle" TargetType="navigation:Page" />

    <!--PageScrollViewerStyle-->
    <Style x:Key="PageScrollViewerStyle" TargetType="ScrollViewer">
        <Setter Property="BorderBrush" Value="Transparent" />
        <Setter Property="BorderThickness" Value="0,1,0,1" />
        <Setter Property="Margin" Value="-58,-15,-58,-15" />
        <Setter Property="Padding" Value="58,0,58,0" />
        <Setter Property="VerticalScrollBarVisibility" Value="Auto" />
        <Setter Property="HorizontalScrollBarVisibility" Value="Auto" />
    </Style>

    <!--ContentPanelStyle-->
    <Style x:Key="ContentPanelStyle" TargetType="StackPanel" />

    <!--HeaderTextStyle-->
    <Style x:Key="HeaderTextStyle" TargetType="TextBlock">
        <Setter Property="Foreground" Value="{StaticResource NavigationForegroundColorBrush}" />
        <Setter Property="FontFamily" Value="{StaticResource HeadingFontFamily}" />
        <Setter Property="FontSize" Value="{StaticResource Heading1FontSize}" />
        <Setter Property="FontWeight" Value="Bold" />
        <Setter Property="TextWrapping" Value="Wrap" />
        <Setter Property="Margin" Value="0,15,0,40" />
        <Setter Property="HorizontalAlignment" Value="Left" />
    </Style>

    <!--ContentTextStyle-->
    <Style x:Key="ContentTextStyle" TargetType="TextBlock">
        <Setter Property="Foreground" Value="{StaticResource NavigationForegroundColorBrush}" />
        <Setter Property="FontFamily" Value="{StaticResource ContentFontFamily}" />
        <Setter Property="FontSize" Value="{StaticResource ContentFontSize}" />
        <Setter Property="TextWrapping" Value="Wrap" />
        <Setter Property="Margin" Value="0,2,0,2" />
        <Setter Property="HorizontalAlignment" Value="Left" />
    </Style>

    <!--PageHyperlinkButtonStyle-->
    <Style x:Key="PageHyperlinkButtonStyle" TargetType="HyperlinkButton">
        <Setter Property="TargetName" Value="_new" />
        <Setter Property="FontSize" Value="{StaticResource DefaultFontSize}" />
        <Setter Property="VerticalAlignment" Value="Center" />
    </Style>

</ResourceDictionary>