@ViewBag.Product["Category"]

@ViewBag.Product.Title

@ViewBag.Product["Price"]

@if(@ViewBag.Product["Pack"]=="IN Stock"){
@ViewBag.Product["Pack"]
}else{
Out Of Stock
}

@ViewBag.Product["Short Description"]

@Html.Raw(@ViewBag.Product.Description)

Error:
Value cannot be null.
Parameter name: value