Value cannot be null. (Parameter 's') at System.Int32.Parse(String s) at Application.AppLogic.Options(HRMates a, ClientFieldClass ClientField) in C:\Users\Admin\source\repos\rarendra\HRMates\HRMates\Logic\VacanciesManagementLogic.cs:line 83 at Application.AppLogic.Options(HRMates p, ClientFieldClass ClientField) in C:\Users\Admin\source\repos\rarendra\HRMates\HRMates\Logic\HiringManagementLogic.cs:line 106 at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor) at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)