I have write the follow code to get the data formated as JSON {"billNumber":"0003","entityActivityId":572,"customerFullName":"التوكيلات التجارية","customerMobileNumber":"0506436506","customerPreviousBalance":0,"issueDate":"2022-08-16","expireDate":"2022-09-23","billItemList":{"name":"*","quantity":1,"unitPrice":900,"discount":0,"discountType":"FIXED","vat":"0.15"}} but I want to be as follwoing: the deferrence is the [] in the details data. {"billNumber":"0003","entityActivityId":572,"customerFullName":"التوكيلات التجارية","customerMobileNumber":"0506436506","customerPreviousBalance":0,"issueDate":"2022-08-16","expireDate":"2022-09-23","billItemList":[{"name":"*","quantity":1,"unitPrice":900,"discount":0,"discountType":"FIXED","vat":"0.15"}]} my code is : dt1 = dt.ToString("yyyy-MM-dd")…