You can use a resource key like this:
<UserControl.Resources>
<SolidColorBrush x:Key="{x:Static local:Foo.MyKey}">Blue</SolidColorBrush>
</UserControl.Resources>
<Grid Background="{StaticResource {x:Static local:Foo.MyKey}}" />
public partial class Foo : UserControl
{
public Foo()
{
InitializeComponent();
var brush = (SolidColorBrush)FindResource(MyKey);
}
public static ResourceKey MyKey { get; } = CreateResourceKey();
private static ComponentResourceKey CreateResourceKey([CallerMemberName] string caller = null)
{
return new ComponentResourceKey(typeof(Foo), caller); ;
}
}