dataTable转换成Json格式

 /// <summary> 
        /// dataTable转换成Json格式 
        /// </summary> 
        /// <param name="dt"></param> 
        /// <returns></returns> 
        public string DataTableToJson(DataTable dtChild)
        {
            StringBuilder jsonBuilder = new StringBuilder();
            jsonBuilder.Append("[");
            for (int i = 0; i < dtChild.Rows.Count; i++)
            {
                jsonBuilder.Append("{");
                for (int j = 0; j < dtChild.Columns.Count; j++)
                {
                    jsonBuilder.Append("\"");
                    jsonBuilder.Append(dtChild.Columns[j].ColumnName);
                    jsonBuilder.Append("\":\"");
                    jsonBuilder.Append(dtChild.Rows[i][j].ToString());
                    jsonBuilder.Append("\",");
                }
                jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
                jsonBuilder.Append("},");
            }
            jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
            jsonBuilder.Append("]");
            return jsonBuilder.ToString();
        }
        #endregion