How to pass selected item id from dropdown list to controller's action?

asp.net, asp.net-mvc, asp.net-mvc-4, c#, razor

Solution

First you need to post your bodyStyleId as a parameter (please note I have used Cars for your controller name, you will need to change that to the actual controller name):

   <div class="form-group">
@Html.LabelFor(model => model.BodyStyle, new { @class = "control-label col-md-2" })
<div class="col-md-10">
    @Html.DropDownListFor(model => model.BodyStyleId, (IEnumerable<SelectListItem>)ViewBag.Styles)
    @Html.ActionLink("Create", "CreateBodyStyle")

    @*here is the problem, can't find a way to pass selected BodyStyle Id to EditBodyStyle action*@
    @Html.ActionLink("Edit", "EditBodyStyle", null, new { bodyStyleId = model.BodyStyleId) 
</div>

Then you need to select it when populating your select list items and send it back to the view:

public ActionResult EditBodyStyle(int bodyStyleId)
{
    var styles = BodyStyles.Select(m => new SelectListItem
                {
                    Value = m.Id.ToString(),
                    Text = m.Name,
                    Selected = bodyStyleId.Equals(m.Id.ToString())

                });
    ViewBag.Styles = styles;
    return View(model);
}

The important part which caught me out when doing this is the following line which selects the list:

 Selected = bodyStyleId.Equals(m.Id.ToString())

And finally use this for you dropdown.

@Html.DropDownListFor(model => model.BodyStyleId, (IEnumerable<SelectListItem>)ViewBag.Styles, "Please select")

Problem

General problem overview: I have a create\edit view for a compound item, where I select lots of options for components from drop down lists. I want to be able to add or edit a specific component, selected in a dropdown list. Here is a short, but complete example: Suppose I have a `Car` model ``` public class Car { public int Id { get; set; } public string Name { get; set; } public BodyStyle BodyStyle { get; set; } public int BodyStyleId { get; set; } } ``` `BodyStyle` is a component of a `Car` aggregate, defined as: ``` public class BodyStyle { public int Id { get; set; } public string Name { get; set; } } ``` Now I have a controller action to create a car, ``` public ActionResult CreateCar() { //BodyStyles is a mock property with all hardcoded BodyStyles, just for demo ViewBag.Styles = new SelectList(BodyStyles, "Id", "Name"); return View(); } ``` Here is the part of the `CreateCar` view, which defines `BodyStyle` dropdown list. ``` <div class="form-group"> @Html.LabelFor(model => model.BodyStyle, new { @class = "control-label col-md-2" }) <div class="col-md-10"> @Html.DropDownListFor(model => model.BodyStyleId, (IEnumerable<SelectListItem>)ViewBag.Styles) @Html.ActionLink("Create", "CreateBodyStyle") @*here is the problem, can't find a way to pass selected BodyStyle Id to EditBodyStyle action*@ @Html.ActionLink("Edit", "EditBodyStyle") </div> </div> ``` Here is the naive implementation of `EditBodyStyle` ``` public ActionResult EditBodyStyle(int bodyStyleId) { return View(BodyStyles.First(b => b.Id == bodyStyleId)); } ``` Is there a way to say to ASP.NET MVC to pass the selected BodyStyle Id from `DropDownListFor` to `EditBodyStyle` action? I've achieved this with javascript, subscribing to `onchange` and storing the selected value, then using it in the link. But the code becomes a mess, since I have near 10 of such components on several views. The functionality is quite simple, so I wonder if I'm missing some ASP.NET MVC feature, that will help me achieve this only using Razor view engine. Here is the resulting view, just to get the whole picture: Where each option of `select` tag is of format: ``` <option value="1">Coupe - 2 door</option> <option value="2">Coupe - 3 door</option> ``` Current implementation (there is no id's in the view example above, but assume dropdown list and link has ids, as noted in the js): ``` $(function () { $("#editBodyStyleLink").click(function () { var id = $("#bodyStylesDropDown").val(); window.location.href = "/Home/EditBodyStyle/?id=" + id; }); }); ```

Original source