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

第二種方法：利用外掛Newtonsoft.Json.dll

Newtonsoft.Json.JsonConvert.SerializeObject(dt);

Newtonsoft.Json.dll 下載地址