我正在尝试使用Html。下拉列表扩展方法,但不知道如何与枚举一起使用它。

假设我有一个这样的枚举:

public enum ItemTypes
{
    Movie = 1,
    Game = 2,
    Book = 3
}

我如何去创建一个下拉与这些值使用Html。下拉列表扩展方法?

或者我最好的办法是简单地创建一个for循环并手动创建Html元素?


当前回答

        ////  ViewModel

        public class RegisterViewModel
          {

        public RegisterViewModel()
          {
              ActionsList = new List<SelectListItem>();
          }

        public IEnumerable<SelectListItem> ActionsList { get; set; }

        public string StudentGrade { get; set; }

           }

       //// Enum Class

        public enum GradeTypes
             {
               A,
               B,
               C,
               D,
               E,
               F,
               G,
               H
            }

         ////Controller action 

           public ActionResult Student()
               {
    RegisterViewModel vm = new RegisterViewModel();
    IEnumerable<GradeTypes> actionTypes = Enum.GetValues(typeof(GradeTypes))
                                         .Cast<GradeTypes>();                  
    vm.ActionsList = from action in actionTypes
                     select new SelectListItem
                     {
                         Text = action.ToString(),
                         Value = action.ToString()
                     };
              return View(vm);
               }

         ////// View Action

   <div class="form-group">
                            <label class="col-lg-2 control-label" for="hobies">Student Grade:</label>
                            <div class="col-lg-10">
                               @Html.DropDownListFor(model => model.StudentGrade, Model.ActionsList, new { @class = "form-control" })
                            </div>

其他回答

我遇到了同样的问题,发现了这个问题,并认为Ash提供的解决方案不是我要寻找的;与内置的HTML . dropdownlist()函数相比,必须自己创建HTML意味着更少的灵活性。

c# 3等使得这非常简单。我有一个名为TaskStatus的枚举:

var statuses = from TaskStatus s in Enum.GetValues(typeof(TaskStatus))
               select new { ID = s, Name = s.ToString() };
ViewData["taskStatus"] = new SelectList(statuses, "ID", "Name", task.Status);

这将创建一个很好的ol' SelectList,可以像在视图中一样使用:

<td><b>Status:</b></td><td><%=Html.DropDownList("taskStatus")%></td></tr>

匿名类型和LINQ使它更加优雅。无意冒犯,阿什。:)

@Html.DropDownListFor(model => model.Type, Enum.GetNames(typeof(Rewards.Models.PropertyType)).Select(e => new SelectListItem { Text = e }))

好吧,我真的是姗姗姗迟了,但无论如何,我已经在博客上讨论了这个主题,在这个主题中我创建了一个EnumHelper类,它可以实现非常简单的转换。

http://jnye.co/Posts/4/creating-a-dropdown-list-from-an-enum-in-mvc-and-c%23

在你的控制器中:

//If you don't have an enum value use the type
ViewBag.DropDownList = EnumHelper.SelectListFor<MyEnum>();

//If you do have an enum value use the value (the value will be marked as selected)    
ViewBag.DropDownList = EnumHelper.SelectListFor(MyEnum.MyEnumValue);

在您看来:

@Html.DropDownList("DropDownList")
@* OR *@
@Html.DropDownListFor(m => m.Property, ViewBag.DropDownList as SelectList, null)

helper类:

public static class EnumHelper
{
    // Get the value of the description attribute if the   
    // enum has one, otherwise use the value.  
    public static string GetDescription<TEnum>(this TEnum value)
    {
        var fi = value.GetType().GetField(value.ToString());

        if (fi != null)
        {
            var attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);

            if (attributes.Length > 0)
            {
                return attributes[0].Description;
            }
        }

        return value.ToString();
    }

    /// <summary>
    /// Build a select list for an enum
    /// </summary>
    public static SelectList SelectListFor<T>() where T : struct
    {
        Type t = typeof(T);
        return !t.IsEnum ? null
                         : new SelectList(BuildSelectListItems(t), "Value", "Text");
    }

    /// <summary>
    /// Build a select list for an enum with a particular value selected 
    /// </summary>
    public static SelectList SelectListFor<T>(T selected) where T : struct
    {
        Type t = typeof(T);
        return !t.IsEnum ? null
                         : new SelectList(BuildSelectListItems(t), "Text", "Value", selected.ToString());
    }

    private static IEnumerable<SelectListItem> BuildSelectListItems(Type t)
    {
        return Enum.GetValues(t)
                   .Cast<Enum>()
                   .Select(e => new SelectListItem { Value = e.ToString(), Text = e.GetDescription() });
    }
}

在。net Core中,你可以这样做:

@Html.DropDownListFor(x => x.Foo, Html.GetEnumSelectList<MyEnum>())

1-创建ENUM

public enum LicenseType
{
    xxx = 1,
    yyy = 2
}

2-创建您的服务类别

public class LicenseTypeEnumService
    {

        public static Dictionary<int, string> GetAll()
        {

            var licenseTypes = new Dictionary<int, string>();

            licenseTypes.Add((int)LicenseType.xxx, "xxx");
            licenseTypes.Add((int)LicenseType.yyy, "yyy");

            return licenseTypes;

        }

        public static string GetById(int id)
        {

            var q = (from p in this.GetAll() where p.Key == id select p).Single();
            return q.Value;

        }

    }

3-在控制器中设置ViewBag

var licenseTypes = LicenseTypeEnumService.GetAll();
ViewBag.LicenseTypes = new SelectList(licenseTypes, "Key", "Value");

绑定你的下拉列表

@Html.DropDownList("LicenseType", (SelectList)ViewBag.LicenseTypes)