This tends to stump people a lot - apparently the roadmap for MVC 5 includes more intuitive DropDownList helpers.
When you do:
@Html.DropDownListFor(x => x.TimeOption ...)
... the HTML helper will do everything in its power not to use the value you set to Selected = true
in your SelectList
. It will:
- Try to get it from
ModelState
- which it won't get on the GET request
- Try to get it from
ViewData
- which it will get, because you have a TimeOption
property on your model.
Only if both of those attempts fail, will it succumb, and use what you asked it to use.
So, in your case, it will use the current value of TimeOption
on your model as the selected value. Which should be fine, because that's what you asked for in your SelectList
anyway ((int)Model.TimeOption
), right?
Wrong. Because it will not cast your property (enum
?) to int
like you do. It will convert it to a string. For an enum
that yields the enumeration's name - e.g. PastMonth
. If TimeOption
is a custom class of yours, it will be the result of ToString()
.
Then, when it doesn't find that string as one of your <select>
values (because they're all integers), it decides not to make anything selected.
In short: SelectListItem.Selected
has no effect on the helper. If your helper call specifies a name (either literally or through a lambda expression), the helper will use anything in ModelState
or ViewData
with that name, and convert it to a string.
In most cases this happens with enumerations. The easiest way to get around it is to use the enumeration's name, rather than its int representation, as the value for the SelectListItem
.
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