How to set default value for ASP.NET MVC DropDownList from model

Question

i am new in mvc. so i populate dropdown this way

public ActionResult New()
{
    var countryQuery = (from c in db.Customers
                        orderby c.Country ascending
                        select c.Country).Distinct();
    List<SelectListItem> countryList = new List<SelectListItem>();
    string defaultCountry = "USA";
    foreach(var item in countryQuery)
    {
        countryList.Add(new SelectListItem() {
                        Text = item, 
                        Value = item, 
                        Selected=(item == defaultCountry ? true : false) });
    }
    ViewBag.Country = countryList;
    ViewBag.Country = "UK";
    return View();       
}

@Html.DropDownList("Country", ViewBag.Countries as List<SelectListItem>)

i like to know how can i populate dropdown from model and also set default value. any sample code will be great help. thanks

Answer 1

Well this is not a great way to do this.

Create a ViewModel that will hold everything you want to be rendered at the view.

public class MyViewModel{

  public List<SelectListItem> CountryList {get; set}
  public string Country {get; set}

  public MyViewModel(){
      CountryList = new List<SelectListItem>();
      Country = "USA"; //default values go here
}

Fill it with the data you need.

public ActionResult New()
{
    var countryQuery = (from c in db.Customers
                        orderby c.Country ascending
                        select c.Country).Distinct();
    MyViewModel myViewModel = new MyViewModel ();

    foreach(var item in countryQuery)
    {
        myViewModel.CountryList.Add(new SelectListItem() {
                        Text = item, 
                        Value = item
                        });
    }
    myViewModel.Country = "UK";



    //Pass it to the view using the `ActionResult`
    return ActionResult( myViewModel);
}

At the view, declare that this view is expecting a Model with type MyViewModel using the following line at the top of the file

@model namespace.MyViewModel 

And at anytime you may use the Model as you please

@Html.DropDownList("Country", Model.CountryList, Model.Country)

Answer 2

You can't set the default value using Html.DropDownList, if you want to have a default value, the property itself should have a default value.

private string country;
public string Country
{
    get { return country ?? "UK"; }
    set { country = value; }
}

Then, when the drop down list renders, as long as "UK" is actually a value for one of the options, it will be automatically set to that.