样例：字符串数组为array，str为字符串数组转换成的字符串 string[] array = { etr, kdgj, 3454, tyt, gff }; string str=string.Join(",",array);

样例DataTable dt=dal.GetUserSonId(UserId);

string str = string.Empty;
if (dt.Rows.Count > 0)
{
str=string.Join(",", dt.Columns["User_Id"]);
}