I’m using this simple code to get my resource for the selected culture

var dictionary = (from d in BaseModel.Instance.ImportCatalog.ResourceDictionaryList
                  where d.Metadata.ContainsKey("Culture")
                  && d.Metadata["Culture"].ToString().Equals(cultureCode)
                  select d).FirstOrDefault();

It works for versions of System.ComponentModel.Composition up to 8 but when I update to 9.0.0 BaseModel.Instance.ImportCatalog.ResourceDictionaryList is null.
Has someone faced this problem and if so is there any workaround?