public void AddAssignment(ContentReference contentRef, ContentReference categoryRef, string scope) { contentRef = contentRef.ToReferenceWithoutVersion(); categoryRef = categoryRef.ToReferenceWithoutVersion(); var matchingAssignments = Store.Items<CategoryAssignment>().Where(ca => ca.ContentPage == contentRef && ca.CategoryPage == categoryRef && ca.Scope == scope); if(matchingAssignments.Count() > 0) { return; } var categoryAssignment = new CategoryAssignment() { ContentPage = contentRef, CategoryPage = categoryRef, Scope = scope }; Store.Save(categoryAssignment); }