namespace StringJoin {    class Program {        static void Main(string[] args) {        List
     
       products=new List
      
       ()        {            new Product(){ProductID=1,ProductName="Iphone5s"},            new Product(){ProductID=2,ProductName="Iphone6s"}        };            //传统的拼凑            string _productid = "";            foreach (var product in products)            {                if (_productid != "")                {                    _productid = _productid + "," + product.ProductID;                }                else                {                    _productid = product.ProductID.ToString();                }            }            Console.WriteLine(_productid);            //委托操作            _productid = "";            products.ForEach(p =>            {                if (_productid != "") {                    _productid = _productid + "," + p.ProductID;                } else {                    _productid = p.ProductID.ToString();                }            });            Console.WriteLine(_productid);            //linq string.join            _productid = "";            //string.Join("", s.Select(it => string.IsNullOrWhiteSpace("") ? it : "" + "," + it));            _productid=string.Join(",", products.Select(it => it.ProductID.ToString()));            Console.WriteLine(_productid);            Console.Read();        }    }    class Product    {        public  int ProductID { get; set; }        public  string ProductName { get; set; }    }}
      
     

记录而已