Adding resource dictionaries to a usercontrol library in wpf - wpf

Question

I have created a user control class library and I used a ResourceDictionary file in it.
Now, I want to use my usercontrol in a WPF application, but I have to add ResourceDictionary file again in my projet! If I don't add it, it brings the ResourceDictionary file, and show an error on MergeDictionaries block!
Am I missing something!?
Resource dictionary is:
<ControlTemplate x:Key="MoveThumbTemplate" TargetType="{x:Type s:MoveThumb}">
<Rectangle Fill="Transparent" Cursor="Hand"/>
</ControlTemplate>
<Style x:Key="ItemStyle" TargetType="ContentControl">
<Setter Property="Width" Value="{Binding RelativeSource={RelativeSource FindAncestor,AncestorType={x:Type Canvas}},Path=ActualWidth}"/>
<Setter Property="MinHeight" Value="60"/>
<Setter Property="Height" Value="60"/>
<Setter Property="Content" Value="MyTextBox"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ContentControl">
<Grid DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
<s:MoveThumb Template="{DynamicResource MoveThumbTemplate}"/>
<ContentPresenter Name="MainControl" Content="{TemplateBinding ContentControl.Content}"
Margin="5,0,10,0"/>
<Grid Opacity="0" Margin="-3">
<s:ResizeThumb Height="3" Cursor="SizeNS" VerticalAlignment="Top" HorizontalAlignment="Stretch"/>
<s:ResizeThumb Height="3" Cursor="SizeNS" VerticalAlignment="Bottom" HorizontalAlignment="Stretch"/>
</Grid>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
adding to user control:
<UserControl.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/Resources/MoveResizeThumb.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</UserControl.Resources>

Answer 1

Give this a try:
<UserControl.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/{YourAssemblyWhereResourceDictionaryIsLocated};component/Resources/MoveResizeThumb.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</UserControl.Resources>

Answer 2

Just to clearify the answer of #Willem: when having additional resources after the merged dictionary, there may appear the error "x:key attribute is required". In this case, those resources have to be inside the resource dictionary:
<UserControl.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary source="/assembly;component/resource.xaml" />
</ResourceDictionary.MergedDictionaries>
<Style TargetType="TextBlock" BasedOn="{StaticResource SetupTextBlockStyle}" />
<ResourceDictionary>
</UserControl.Resources>
<Grid />

Answer 3

In response to #ThisHandleNotInUse and #OliverAssad comments in the accepted answer.
In case of x:Key attribute required error, the ResourceDictionary tag should be modified as follows:
<UserControl.Resources x:Key="myKey">
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/{YourAssemblyWhereResourceDictionaryIsLocated};component/Resources/MoveResizeThumb.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</UserControl.Resources>

Answer 4

Another way is to add the resource at an application level
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="ProjectStyles.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>