Newtonsoft.Json DataSet/DataTable转化为JSON字符串

1.添加Newtonsoft.Json引用（我用的VS2015 ASP.NET应用程序默认有此引用）；
2.引入命名空间；
using Newtonsoft.Json;
3.转换为JSON字符串格式；

public string Get(int id)        {            try            {                SqlConnection sqlConnection =                    new SqlConnection(                        "Data Source=127.0.0.1;Initial Catalog=GaryWeb;Integrated Security=True;User Id=sa;Password=123456");                sqlConnection.Open();                string sql = "select * from Users";                DataSet dataSet = new DataSet();                SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(sql, sqlConnection);                sqlDataAdapter.Fill(dataSet);                return JsonConvert.SerializeObject(dataSet);            }            catch (Exception ex)            {                return ex.ToString();            }        }

关键代码：JsonConvert.SerializeObject(dataSet);