DropDownListFor not selecting selected

0
votes

I have a dropdownlistfor which lists selectable dates. I want to pre-select a certain date but even though it's marked as "Selected" it doesn't show as the selected when looking at the dropdownlist.

enter image description here

<%=Html.DropDownListFor(model => model.SelectDropOfDate, Model.DropOffDates, new { id = "dropOfDate" })%>

In one thread that I read they said that "model.SelectDropOfDate" (in this case) is the selected item and if that's the case, should I select the value or the text in order for it to match the one in the list? 

(the list of dates).Where(x=>x.Selected).Select(z=>z.Value).ToString();

(Ps: I've tried both value and text and none of them worked)

Any ideas?

3
c#asp.net-mvcdatetimedropdownlistfor
"model.SelectDropOfDate" - NOT true! :) So does getDropOffDates returns the model to the view where your DropDownListFor is? Because if it is then it means your model is a collection and doing Model.DropOffDates is not right? - von v.
von v. I am not sure what you mean, could you describe it further? - Jennica
Html helpers use value from modelstate as first selection. You can try clearing modelstate before returning view and see if the problem is on the server side or the client side. if the problem still occurs, its probably some script that messes with selected value. - maxlego

3 Answers

1
votes

You should set the value of the SelectDropOfDate property on your model instead to the corresponding Value (not Text). For example:

model.SelectDropOfDate = departureDate.ToString("d/M/yyyy", new DateTimeFormatInfo());

Also notice that the value must have an exact match in order for the corresponding element to be preselected.

0
votes

It seems like DropDownListFor in asp.mvc has this bug,the 'selected' will not work i thought beacuse the htmlhelper of Lamda Expression covered the 'selected' property.So just make sure model.SelectDropOfDate=departureDate.ToString("d/M/yyyy", new DateTimeFormatInfo()) has run. I have tried this in Mvc3 and it will chosen write item when the value really matches.

0
votes

My appologies, there was a dumb javascript overwriting my selected which screwed things up. I did create a testproject to verify the suggestions here though and here's what I found out (for others that read this thread):

The selectedDropOfDate does not have to be filled in, in fact, it didnt work at all when I had that filled in. Having the List have one item that is marked as selected = true works well enough.

Example code

Model:

public class Home
    {
        public string Selected { get; set; }
        public List<SelectListItem> Items { get; set; }
    }

Controller:

public ActionResult Index()
        {
            var model = new Home();
            model.Items = GetItems(DateTime.Now, DateTime.Now.AddDays(3));
            return View(model);
        }

        private List<SelectListItem> GetItems(DateTime start, DateTime end)
        {
            var dates = new List<DateTime>();
            for (double i = 0; i < 100; i++)
            {
                dates.Add(start.AddDays(i + 1));
            }

            var selectList = new List<SelectListItem>();
            selectList.AddRange(dates.Select(x => new SelectListItem
            {
                Selected = x.Date == end.Date,
                Text = x.ToString("d.M.yyyy"),
                Value = x.ToString("d/M/yyyy", new DateTimeFormatInfo())
            }));

            return selectList;
        }

View:

<%= Html.DropDownListFor(model => model.Selected, Model.Items) %>