Question

I am new to MVC3
I am finding it difficult to create an dropdown.I have gone through all the other related questions but they all seem to be complex
I jus need to create a dropdown and insert the selected value in database

Here is what i have tried:

//Model class:
    public int Id { get; set; }
    public SelectList hobbiename { get; set; }
    public string filelocation { get; set; }
    public string hobbydetail { get; set; }
//Inside Controller
public ActionResult Create()
    {
        var values = new[]
        { 
            new { Value = "1", Text = "Dancing" },
            new { Value = "2", Text = "Painting" }, 
            new { Value = "3", Text = "Singing" },
        };
        var model = new Hobbies
        {
           hobbiename = new SelectList(values, "Value", "Text")
        }; 
        return View();
    } 
//Inside view
 <div class="editor-label">
        @Html.LabelFor(model => model.hobbiename)
    </div>
    <div class="editor-field">
        @Html.DropDownListFor(     x => x.hobbiename,     Model.hobbiename ) 
        @Html.ValidationMessageFor(model => model.hobbiename)
    </div>

I get an error:System.MissingMethodException: No parameterless constructor defined for this object

Answer 1

You are not passing any model to the view in your action. Also you should not use the same property as first and second argument of the DropDownListFor helper. The first argument that you pass as lambda expression corresponds to a scalar property on your view model that will hold the selected value and which will allow you to retrieve this value back when the form is submitted. The second argument is the collection.

So you could adapt a little bit your code:

Model:

public class Hobbies
{
    [Required]
    public string SelectedHobbyId { get; set; }
    public IEnumerable<SelectListItem> AvailableHobbies { get; set; }

    ... some other properties that are irrelevant to the question 
}

Controller:

public class HomeController: Controller
{
    public ActionResult Create()
    {
        // obviously those values might come from a database or something
        var values = new[]
        { 
            new { Value = "1", Text = "Dancing" },
            new { Value = "2", Text = "Painting" }, 
            new { Value = "3", Text = "Singing" },
        };

        var model = new Hobbies
        {
           AvailableHobbies = values.Select(x => new SelectListItem
           {
               Value = x.Value,
               Text = x.Text
           });
        }; 
        return View(model);
    }     

    [HttpPost]
    public ActionResult Create(Hobbies hobbies)
    {
        // hobbies.SelectedHobbyId will contain the id of the element
        // that was selected in the dropdown
        ...
    }
}

View:

@model Hobbies
@using (Html.BeginForm())
{
    @Html.LabelFor(x => x.SelectedHobbyId)
    @Html.DropDownListFor(x => x.SelectedHobbyId, Model.AvailableHobbies) 
    @Html.ValidationMessageFor(x => x.SelectedHobbyId)

    <button type="submit">Create</button>
}