Validation Error Compiler error(s) encountered processing expression Operator '+' is not defined for types 'String' and 'Newtonsoft.Json.Linq.JObject'. Main.xaml

[ashwini.mali]

“branchCode=”+branchCode+“&billType=”+billType+“&billDate=”+billDate +“&custCode=”+custCode+“&billNo=”+billNo+“&totalBillAmount=”+totalBillAmount+“&productSearchKey=”+ProductSearchKey