ResourceDictionary in App.xaml won't load

Question

I have a set of styles that I want to load to use as a StaticResource throughout my app: Styles.xaml

Everything works fine if I include the style in each window or page:

<Window x:Class="MainWindow"
    <Window.Resources>        
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="Resources/Styles.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>        
    </Window.Resources>
</Window>

If I try to include the style in my app resource, it throws an error that it can't find the MainWindow.xaml resource.

<Application x:Class="App"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         StartupUri="MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="Resources/Styles.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

Anyone know why I can't include this in my app resource?

Answer 1

I'm not sure why the MergedDictionary doesn't work, but if I add the style as a standalone resource it works fine.

<Application x:Class="App"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:local="clr-namespace:Excavator"  
         StartupUri="MainWindow.xaml">
    <Application.Resources>
         <ResourceDictionary Source="Resources/Styles.xaml" />        
    </Application.Resources>
</Application>

Answer 2

I would comment on your post but there's a 50 rep requirement...

Have you tried setting a key for the ResourceDictionary?

       <ResourceDictionary x:Key="Styles" Source="Resources/Styles.xaml" />