Convert Data table to Json

public string GetJson(DataTable dt)

     {

         System.Web.Script.Serialization.JavaScriptSerializer serializer = new

         System.Web.Script.Serialization.JavaScriptSerializer();

         List<Dictionary<string, object>> rows =

           new List<Dictionary<string, object>>();

         Dictionary<string, object> row = null;

         foreach (DataRow dr in dt.Rows)

         {

             row = new Dictionary<string, object>();

             foreach (DataColumn col in dt.Columns)

             {

                 row.Add(col.ColumnName.Trim(), dr[col]);

             }

             rows.Add(row);

         }

         return serializer.Serialize(rows);

     }