public void AddCustomer(Customer newCustomer) { List <Customer> getCustomers = repo.GetAllCustomers(); foreach (var customer in getCustomers) { if (customer.Name.Equals(newCustomer.Name)) { Log.Error($"Customer already exists. Name: {newCustomer.Name}"); throw new Exception($"\nCustomer name {newCustomer.Name} already exists. Not you? Please enter a unique name."); } } repo.AddACustomer(newCustomer); }