如何将颜色绑定到MahApps Metro资源？

Question

I'm using the MahApps Metro theme and everything mostly works fine except for fills. I would like to bind my fill color to the color in the theme and have it change according when changing between light/dark mode. Does anyone know how to do this?

My App.xaml:

<Application 
...>
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                ...
                <!-- Accent and AppTheme setting -->
                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/Teal.xaml" />
                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/BaseLight.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

What I want to change:

<Rectangle Fill="??????"">

Answer 1

Inside your Application.Resources you put:

<ResourceDictionary.ThemeDictionaries>
    <ResourceDictionary x:Key="Dark">
        <SolidColorBrush x:Key="RectangleFill" Color="White"/>
    </ResourceDictionary>

    <ResourceDictionary x:Key="Light">
        <SolidColorBrush x:Key="RectangleFill" Color="Blue"/>
    </ResourceDictionary>
 </ResourceDictionary.ThemeDictionaries>

Then you should bind the Rectangle.Fill to the ThemeResource "RectangleFill"

<Rectangle Height="200" Width="400" Fill="{ThemeResource RectangleFill}"></Rectangle>