如何使用下拉列表的数据注释？

Question

在MVC3中,数据注释可用于加速UI开发和验证; 即.

    [Required]
    [StringLength(100, ErrorMessage = "The {0} must be at least {2} characters long.", MinimumLength = 6)]
    [DataType(DataType.Password)]
    [Display(Name = "New password")]
    public string NewPassword { get; set; }

但是,如果对于移动应用程序,没有字段标签,则只会从数据库中填充下拉列表.我将如何以这种方式定义它？

    [Required]
    [DataType(DataType.[SOME LIST TYPE???])]
    [Display(Name = "")]
    public string Continent { get; set; }

最好不要使用这种方法吗？

Answer 1

像这样更改您的ViewModel

public class RegisterViewModel
{
   //Other Properties

   [Required]
   [Display(Name = "Continent")]
   public string SelectedContinent { set; get; }
   public IEnumerable<SelectListItem> Continents{ set; get; }

}

在GETAction方法中,设置从数据库获取数据并设置ViewModel的Continents Collection属性

public ActionResult DoThatStep()
{
  var vm=new RegisterViewModel();
  //The below code is hardcoded for demo. you may replace with DB data.
  vm.Continents= new[]
  {
    new SelectListItem { Value = "1", Text = "Prodcer A" },
    new SelectListItem { Value = "2", Text = "Prodcer B" },
    new SelectListItem { Value = "3", Text = "Prodcer C" }
  }; 
  return View(vm);
}

并在你的View(DoThatStep.cshtml)中使用它

@model RegisterViewModel
@using(Html.BeginForm())
{
  @Html.ValidationSummary()

  @Html.DropDownListFor(m => m.SelectedContinent, 
               new SelectList(Model.Continents, "Value", "Text"), "Select")

   <input type="submit" />
}

现在,这将使您的DropDown必填字段.