Each Dictionary entry must have an associated key attribute

Question

I am programming w Windows 8.1 App using C# and the MVVM-Light Toolkit from GalaSoft.

All I have is the code below:

<Application.Resources>
    <vm:ViewModelLocator x:Key="Locator" xmlns:vm="using:Scedule.ViewModel" />

    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Resource Dictionaries/StandardStyles.xaml"/>
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>      
</Application.Resources>

The error "Each Dictionary entry must have an associated key attribute" occurs and only disappears when I either remove

    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Resource Dictionaries/StandardStyles.xaml"/>
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary> 

or

    <vm:ViewModelLocator x:Key="Locator" xmlns:vm="using:Scedule.ViewModel" />

Can anyone tell me what the problem here is?

Answer 1

Note that Application.Resources requires an instance of ResourceDictionary, so you have to do something like this:

<Application.Resources>    
  <ResourceDictionary>
    <vm:ViewModelLocator x:Key="Locator" xmlns:vm="using:Scedule.ViewModel" />
    <ResourceDictionary.MergedDictionaries>
        <ResourceDictionary Source="Resource Dictionaries/StandardStyles.xaml"/>
    </ResourceDictionary.MergedDictionaries>
  </ResourceDictionary>      
</Application.Resources>

So it's not strange at all, it's also not a bug. If you want your ResourceDictionary to be treated as a resource, you of course have to provide some Key for it, however in this case you really want to assign an instance of ResourceDictionary to the Application.Resources