MVC3 DropDownListFor - a simple example?

问题

I\'m having trouble with DropDownListFor in my MVC3 app. I was able to use StackOverflow to figure out how to get them to appear on the View, but now I don\'t know how to capture the values in its corresponding properties on the View Model when it\'s submitted. In order to get this to work I had to create an inner class that had an ID and a value property, then I had to use an IEnumerable<Contrib> to satisfy the DropDownListFor parameter requirements. Now, however, how is MVC FW supposed to map the value that is selected on this drop-down back into the simple string property on my view model?

public class MyViewModelClass
{
    public class Contrib
    {
        public int ContribId { get; set; }
        public string Value { get; set; }
    }

    public IEnumerable<Contrib> ContribTypeOptions = 
        new List<Contrib>
        {
            new Contrib {ContribId = 0, Value = \"Payroll Deduction\"},
            new Contrib {ContribId = 1, Value = \"Bill Me\"}
        };

    [DisplayName(\"Contribution Type\")]
    public string ContribType { get; set; }
}

In my View I place the dropdown on the page like this:

<div class=\"editor-label\">
    @Html.LabelFor(m => m.ContribType)
</div>
<div class=\"editor-field\">
    @Html.DropDownListFor(m => m.ContribTypeOptions.First().ContribId, 
             new SelectList(Model.ContribTypeOptions, \"ContribId\", \"Value\"))
</div>

When I submit the form the ContribType is (of course) null.

What is the correct way to do this?

回答1:

You should do like this:

@Html.DropDownListFor(m => m.ContribType, 
                new SelectList(Model.ContribTypeOptions, 
                               "ContribId", "Value"))

Where:

m => m.ContribType

is a property where the result value will be.

回答2:

I think this will help : In Controller get the list items and selected value

public ActionResult Edit(int id)
{
    ItemsStore item = itemStoreRepository.FindById(id);
    ViewBag.CategoryId = new SelectList(categoryRepository.Query().Get(), 
                                        "Id", "Name",item.CategoryId);

    // ViewBag to pass values to View and SelectList
    //(get list of items,valuefield,textfield,selectedValue)

    return View(item);
}

and in View

@Html.DropDownList("CategoryId",String.Empty)

回答3:

For binding Dynamic Data in a DropDownList you can do the following:

Create ViewBag in Controller like below

ViewBag.ContribTypeOptions = yourFunctionValue();

now use this value in view like below:

@Html.DropDownListFor(m => m.ContribType, 
    new SelectList(@ViewBag.ContribTypeOptions, "ContribId", 
                   "Value", Model.ContribTypeOptions.First().ContribId), 
    "Select, please")

回答4:

     @Html.DropDownListFor(m => m.SelectedValue,Your List,"ID","Values")

Here Value is that object of model where you want to save your Selected Value

来源：https://stackoverflow.com/questions/7142961/mvc3-dropdownlistfor-a-simple-example

标签

asp.net-mvc-3

html.dropdownlistfor