This line is the most important:
TrainingManegments.Controllers.HomeController.RegisterSearch(Nullable`1 eduId, String St_Mail)
I'd check what value of
eduId
variable is passed to the controller... Seems, it can't be
null
. Try to convert
null
value of
Nullable<t>[
^] to proper value:
int? eduId = null;
eduId = eduId ?? 0;
or provide error handler for such of situation.