如何在强类型视图中为下拉列表的可选字符串设置id？

Question

My Strongly typed view consists of drop-down like below:

  @Html.DropDownListFor(model => model.Text, ViewBag.Drop as SelectList,"Select a bus");

Above optional string is 'Select a Bus'.But I can't set id property as "0" for this.Remaining id values and text I fetch it from DB.I know I can put even optional string in DB table only.But I don't want like so. So if I didn't select anything,and if I submit then 'null' value to Text property of model class in controller method which I don't want.I want's to return only "0" in this case.So My Controller is below.

public ActionResult Dropdown(DropdownCheck drpchk)
    {
        if (ModelState.IsValid)
        {
            return View("some name");
        }

        return View("Dropdown");
    }

So how do I set id value to optional string..?

Answer 1

Add another SelectListItem after retrieving from DB:

var buses = db.Buses.Select(t => new SelectListItem
{
     Text = t.SomeText,
     Value = t.SomeValue
}).ToList();

buses.Add(new SelectListItem
{
     Text = "--Select a Bus--",
     Value = "0",
     Selected = true
});

ViewBag.Drop = buses;

In your view:

 @Html.DropDownListFor(m => m.Text, ViewBag.Drop as IEnumerable<SelectListItem>);