为什么只返回了一个值？而不是一个数组？

C# code

        private string OutputPrice()        {            string sql = "select * from YuyaoPrice where ClassId=1 and SmallId=435";            DataTable dt = DBclass.ExecSel(sql);            for (int i = 0; i < dt.Rows.Count; i++)            {                string a = dt.Rows[i]["NewPrice"].ToString();                string b = ",";                string c = a + b;                Price = c.ToString();                            }            return Price;                  } public string Price = string.Empty;        protected void Page_Load(object sender, EventArgs e)        {            Price = OutputPrice();            Response.Write(Price.ToString());//读出来只有：15900，        }

以上代码只返回了一个值：15900，正确的话应该是：15900，16000,16000,16000，

[解决办法]
应该不是代码的问题，去数据库里看一下，也许就真的只有一行数据返回。
[解决办法]
Price = c.ToString(); 当然只返回一个值了

Price += c.ToString(); 而且可能你for循环里算法还得改改
[解决办法]
for (int i = 0; i < dt.Rows.Count; i++)
{
object a = dt.Rows[i]["NewPrice"];
if(a != null)
{
Price += a.ToString();
}
if(i < dt.Rows.Count - 1)
{
Price += ",";
}
}

for循环改成这样试试，我没测试过
[解决办法]
这样：
private string OutputPrice()
{
string _price="";
string sql = "select * from YuyaoPrice where ClassId=1 and SmallId=435";
DataTable dt = DBclass.ExecSel(sql);

for (int i = 0; i < dt.Rows.Count; i++)
{
string a = dt.Rows[i]["NewPrice"].ToString();
string b = ",";
string c = a + b;
_price += c.ToString();

}
return _price;

}
[解决办法]
应该用list<>
[解决办法]

C# code

 private List<string> OutputPrice()        {            string sql = "select * from YuyaoPrice where ClassId=1 and SmallId=435";            DataTable dt = DBclass.ExecSel(sql);            for (int i = 0; i < dt.Rows.Count; i++)            {                string a = dt.Rows[i]["NewPrice"].ToString();                string b = ",";                string c = a + b;                Prices.Add(c.ToString());            }            return Prices;        }        public List<string> Prices = new List<string>();        protected void Page_Load(object sender, EventArgs e)        {            Prices = OutputPrice();            foreach (string Price in Prices)            {                Response.Write(Price.ToString());//读出来只有：15900，            }        }
[解决办法]
你这样是循环赋值，并没有追加，肯定最多只有一个了。
[解决办法]
探讨

都不行。。。。

[解决办法]
注意红色部分 
 
private string OutputPrice()
       {
           string sql = "select * from YuyaoPrice where ClassId=1 and SmallId=435";
           DataTable dt = DBclass.ExecSel(sql);
           string c="";
           for (int i = 0; i < dt.Rows.Count; i++)
           {
               string a = dt.Rows[i]["NewPrice"].ToString();
               string b = ",";
               c += a + b;
               Price = c.ToString();
              
           }
           return Price;
        
       }
[解决办法]
把 = 改为 +=
[解决办法]
private string OutputPrice()
       {
          string Price=string.Empty;
           string sql = "select * from YuyaoPrice where ClassId=1 and SmallId=435";
           DataTable dt = DBclass.ExecSel(sql);
           for (int i = 0; i < dt.Rows.Count; i++)
           {
                Price += dt.Rows[i]["NewPrice"].ToString()+",";
                             
           }
           return Price;
        
       }