list 屬性字段直接轉成字符串數組

List<Car> cars = //whatever; string concat = String.Join(",", cars.Select(c => c.Name).ToArray());

string concat = cars.Select(c => c.Name).Aggregate(new StringBuilder(), (sb, current) => { return sb.Length == 0 ? sb.Append(current) : sb.AppendFormat(",{0}", current); }).ToString();