Classic.xaml PresentationUIStyleResources?

Dear Experts

I getting an error in wpf  vb. net while apply classic.xmal theme and I have already added reference as

System.Windows.Forms

how to salve it?

rror 3 The name "PresentationUIStyleResources" does not exist in the namespace "clr-namespace:System.Windows.Documents;assembly=PresentationUI". D:\MANOJ\Ocean\Ocean\Themes\Classic.xaml 1858 39 Ocean

Thanks & Regards Manoj Patel