本文转自:https://stackoverflow.com/questions/27456983/pass-a-viewbag-instance-to-a-hiddenfor-field-in-razor
You are getting this error because ViewBag is dynamic type. You can use ViewModel instead of ViewBag to solve this problem.
Alternatively you can use following or plain html as suggested by iceburg:
@Html.Hidden("id", (string)ViewBag.PortfolioId)
https://stackoverflow.com/questions/10179015/mvc-razor-html-helper-syntax-viewbag-in-html-hidden-object-parameter
Try casting the return value to object
:
@Html.Hidden("hiddenDate", (object)ViewBag.myDate.ToString("dd.MM.yyyy"))