public void SelfRegistration(CourseOffering course, UserAccount account) { // Look for the course var existingCourse = FileContext.FindCourse(course); if (existingCourse == null) { course.Students.Add(account.LoginName, account); FileContext.CreateCourse(course); } else { if (existingCourse.Students.ContainsKey(account.LoginName)) { throw new Exception("Already registered"); } existingCourse.Students.Add(account.LoginName, account); FileContext.UpdateCourse(existingCourse); } }