Sharing DataTemplates between controls - wpf

Question

I have a ContentPresenter in a couple of places in my application with exactly the same DataTemplates. For now I simply copy-pasted them, but I'd like to clean that up and share them between ContentPresenter instances. I tried this approach:
<ContentControl Content="{Binding DataEditorViewModel}">
<ContentControl.Resources>
<ResourceDictionary Source="pack://application:,,,/LogAnalyzer;component/PredicateDataEditors.xaml" />
</ContentControl.Resources>
</ContentControl>
Application runs, but DataTemplates aren't being applied, I simply see name of class being ContentPresenter's content instead of defined template. I put templates in ResourceDictionary in the following way:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:LogAnalyzer"
xmlns:p="clr-namespace:LogAnalyzer.BusinessLogic.ViewModels.Processing;assembly=LogAnalyzer.BusinessLogic"
xmlns:xwt="http://schemas.xceed.com/wpf/xaml/toolkit">
<DataTemplate DataType="{x:Type p:MessageRuleDataEditorViewModel}" x:Key="{x:Type p:MessageRuleDataEditorViewModel}">
(...)
</DataTemplate>
(...)
</ResourceDictionary>
What should I do to embed DataTemplates correctly in ContentPresenter's resources?

Answer 1

if you define this data template in your app.xaml:
<DataTemplate DataType="{x:Type p:MessageRuleDataEditorViewModel}">
<TextBlock Text="testing" />
</DataTemplate>
and then do something like:
<ListBox ItemsSource="{Binding MyCollectionOfMessageRuleDataEditorViewModels}"/>
then your data template is automatically applied to every object of that same type. dont define a key for your global templates