Question

I’m having a problem with WPF resources accessing external style info in an external ResourceDictionary through StaticResources.

I have inherited a bunch of code that uses a lot of DynamicResources in their WPF to get style information from a Shared.xaml. I would rather them be StaticResources so that the designer view becomes useful. I discovered that I can add a ResourceDictionary in the .Resources of the thing, which works fine UNLESS there is already a .Resources using in the WPF. In that case I am told I need to add a x:Key to my ResourceDictionary. I do that except that now I don’t know how to use that key to find the resources statically.

Minimal example:

<UserControl x:Class="myClass"
  ...>
  <UserControl.Resources>
    <ResourceDictionary x:Key="Shared.xaml" Source="/ExteralResource;component/Shared.xaml"/>
    <BooleanToVisibilityConverst x:Key="BoolToVis">
  </UserControl.Resources>

  <TextBlock Background="{StaticResource BrushFromSharedXAML}" /> <!-- Never finds BrushSharedXAML -->
</UserControl>

Any ideas?

Answer 1

<UserControl.Resources>
  <ResourceDictionary>
      <ResourceDictionary.MergedDictionaries>
          <ResourceDictionary Source="/ExteralResource;component/Shared.xaml"/>
      </ResourceDictionary.MergedDictionaries>
      <BooleanToVisibilityConverst x:Key="BoolToVis">
  </ResourceDictionary>
</UserControl.Resources>

Though, be aware that doing this in each usercontrol is going to eat a lot of RAM, because you’re actually creating a new instance of the Shared.xaml ResourceDictionary for every instance of this control at runtime. You should take a look at SharedResourceDictionary