How to combine imported and local resources in WPF user control

Question

I'm writing several WPF user controls that need both shared and individual resources.

I have figured out the syntax for loading resources from a separate resource file:

<UserControl.Resources>     <ResourceDictionary Source="ViewResources.xaml" /> </UserControl.Resources> 

However, when I do this, I cannot also add resources locally, like:

<UserControl.Resources>     <ResourceDictionary Source="ViewResources.xaml" />     <!-- Doesn't work: -->     <ControlTemplate x:Key="validationTemplate">         ...     </ControlTemplate>     <style x:key="textBoxWithError" TargetType="{x:Type TextBox}">         ...     </style>     ... </UserControl.Resources> 

I've had a look at ResourceDictionary.MergedDictionaries, but that only lets me merge more than one external dictionary, not define further resources locally.

I must be missing something trivial?

It should be mentioned: I'm hosting my user controls in a WinForms project, so putting shared resources in App.xaml is not really an option.

Answer 1

I figured it out. The solution involves MergedDictionaries, but the specifics must be just right, like this:

<UserControl.Resources>     <ResourceDictionary>         <ResourceDictionary.MergedDictionaries>             <ResourceDictionary Source="ViewResources.xaml" />         </ResourceDictionary.MergedDictionaries>         <!-- This works: -->         <ControlTemplate x:Key="validationTemplate">             ...         </ControlTemplate>         <style x:key="textBoxWithError" TargetType="{x:Type TextBox}">             ...         </style>         ...     </ResourceDictionary> </UserControl.Resources> 

That is, the local resources must be nested within the ResourceDictionary tag. So the example here is incorrect.

Answer 2

You can define local resources inside MergedDictionaries section:

<UserControl.Resources>     <ResourceDictionary>         <ResourceDictionary.MergedDictionaries>             <!-- import resources from external files -->             <ResourceDictionary Source="ViewResources.xaml" />              <ResourceDictionary>                 <!-- put local resources here -->                 <Style x:key="textBoxWithError" TargetType="{x:Type TextBox}">                     ...                 </Style>                 ...             </ResourceDictionary>         </ResourceDictionary.MergedDictionaries>     </ResourceDictionary> </UserControl.Resources>