ASP.NET MVC 2 DropDownList not Setting the Selected Value

Question

I am trying to populate the dropdown value with the selected value. I referred to related articles and I am doing the same. Still Dropdown is not populating with the selected Value. Not sure what I am missing.

Controller Code:

var RegionId = new[] { 
                new RegionKeyValues { RegionId = 1, RegionValue = "A" }, 
                new RegionKeyValues { RegionId = 2, RegionValue = "B" }, 
                new RegionKeyValues { RegionId = 3, RegionValue = "D" } 
            };
ViewData["RegionId"] = new SelectList(RegionId, "RegionId", "RegionValue", 1);

View Code:

<%= Html.DropDownList("RegionId",
                      (SelectList)ViewData["RegionId"],
                      "-- Select --")%>

I don't think the question is clear. The drop down list doesn't populate the list with the contents of the RegionId list? Or you think that the list is supposed to preselect a value and it is not? — Zach Green, Feb 08 '12 at 16:42
Dropdown is populating fine with those 3 records. But it is not setting to "A" — Rita, Feb 08 '12 at 16:44
No.. It is not Dupe... There are couple of related... But My Dropdown is not setting to selected value of "A" that is 1. — Rita, Feb 08 '12 at 16:45

score 5 · Accepted Answer · answered Feb 08 '12 at 16:44

5

I think the problem is with the fact your property name is RegionId, as well as the ViewData name. Change one and see what happens.

answered Feb 08 '12 at 16:44

Tr1stan

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score 2 · Answer 2 · edited May 23 '17 at 09:59

I'd try<%=Html.DropDownList("RegionId", new SelectList((IEnumerable)ViewData["RegionId"], "Value", "Text",1),"-- Select --")%>

Setting the value in the actual view.

Also in general I would create a strongly typed ViewModel and create properties storing the select list values as an IEnumerable<SelecListItem>

Then you can do

<%=Html.DropDownListFor(a=>a.RegionId, new SelectList(Model.Regions, "Value", "Text"),"-- Select --")`%>

Where RegionId would be the actual value to set to and Model.Regions stores the list of possible regions.

In general I feel a good approach to controllers and lists, viewmodels etc is in this post here

jim tollan · Answer 3 · 2012-02-08T18:18:05.100

Rita,

Here's my effort on this:

the model:

namespace MvcApplication1.Models
{
    public class RegionKeyValues
    {
        public int RegionId { get; set; }
        public string RegionValue { get; set; }
    }

    public class RegionKeyValuesViewModel
    {
        public int SelectedRegionId { get; set; }
        public IEnumerable<RegionKeyValues> RegionList { get; set; }
    }
}

Controller action:

public ActionResult Index()
{
    var regionList = new[] { 
        new RegionKeyValues { RegionId = 1, RegionValue = "A" }, 
        new RegionKeyValues { RegionId = 2, RegionValue = "B" }, 
        new RegionKeyValues { RegionId = 3, RegionValue = "D" } 
    };

    var viewModel = new RegionKeyValuesViewModel
    {
        RegionList = regionList, 
        SelectedRegionId = 1 // hardcoded here, but in real-life, from the db
    };

    ViewData.Model = viewModel;

    return View();
}

View code (in Razor):

@model MvcApplication1.Models.RegionKeyValuesViewModel
@{
    ViewBag.Title = "Home Page";
}

@Html.DropDownListFor(a => a.SelectedRegionId, 
    new SelectList(Model.RegionList, "RegionId", "RegionValue", 
        Model.SelectedRegionId), "-- Select --")

so basically, I'm passing a strongly typed ViewModel down to the view and setting the selected RegionId in the controller and passing that to Model.SelectedRegionId. In a real app, you'd obviously be getting the viewModel from the db or some other structure.

worth considering as an alternative.

ASP.NET MVC 2 DropDownList not Setting the Selected Value

3 Answers3