MVC3 Razor DropDownListFor Enums

Question

Trying to get my project updated to MVC3, something I just can't find:

I have a simple datatype of ENUMS:

public enum States() {   AL,AK,AZ,...WY } 

Which I want to use as a DropDown/SelectList in my view of a model that contains this datatype:

public class FormModel() {     public States State {get; set;} } 

Pretty straight forward: when I go to use the auto-generate view for this partial class, it ignores this type.

I need a simple select list that sets the value of the enum as the selected item when I hit submit and process via my AJAX - JSON POST Method.

And than the view (???!):

    <div class="editor-field">         @Html.DropDownListFor(model => model.State, model => model.States)     </div> 

thanks in advance for the advice!

Answer 1

I found a way simpler solution for this here: http://coding-in.net/asp-net-mvc-3-method-extension/

using System; using System.Linq.Expressions; using System.Web; using System.Web.Mvc; using System.Web.Mvc.Html;  namespace EnumHtmlHelper.Helper {         public static class EnumDropDownList     {         public static HtmlString EnumDropDownListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> modelExpression, string firstElement)         {             var typeOfProperty = modelExpression.ReturnType;             if(!typeOfProperty.IsEnum)                 throw new ArgumentException(string.Format("Type {0} is not an enum", typeOfProperty));                  var enumValues = new SelectList(Enum.GetValues(typeOfProperty));             return htmlHelper.DropDownListFor(modelExpression, enumValues, firstElement); }   }   } 

One line in razor will do it:

@Html.DropDownListFor(model => model.State, new SelectList(Enum.GetValues(typeof(MyNamespace.Enums.States)))) 

You can also find code for doing it with an extension method in the linked article.

Answer 2

I've just made one for my own project. The code below is part of my helper class, I hope that I got all methods needed. Write a comment if it doesn't work, and I'll check again.

public static class SelectExtensions {      public static string GetInputName<TModel, TProperty>(Expression<Func<TModel, TProperty>> expression)     {         if (expression.Body.NodeType == ExpressionType.Call)         {             MethodCallExpression methodCallExpression = (MethodCallExpression)expression.Body;             string name = GetInputName(methodCallExpression);             return name.Substring(expression.Parameters[0].Name.Length + 1);          }         return expression.Body.ToString().Substring(expression.Parameters[0].Name.Length + 1);     }      private static string GetInputName(MethodCallExpression expression)     {         // p => p.Foo.Bar().Baz.ToString() => p.Foo OR throw...         MethodCallExpression methodCallExpression = expression.Object as MethodCallExpression;         if (methodCallExpression != null)         {             return GetInputName(methodCallExpression);         }         return expression.Object.ToString();     }      public static MvcHtmlString EnumDropDownListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression) where TModel : class     {         string inputName = GetInputName(expression);         var value = htmlHelper.ViewData.Model == null             ? default(TProperty)             : expression.Compile()(htmlHelper.ViewData.Model);          return htmlHelper.DropDownList(inputName, ToSelectList(typeof(TProperty), value.ToString()));     }      public static SelectList ToSelectList(Type enumType, string selectedItem)     {         List<SelectListItem> items = new List<SelectListItem>();         foreach (var item in Enum.GetValues(enumType))         {             FieldInfo fi = enumType.GetField(item.ToString());             var attribute = fi.GetCustomAttributes(typeof(DescriptionAttribute), true).FirstOrDefault();             var title = attribute == null ? item.ToString() : ((DescriptionAttribute)attribute).Description;             var listItem = new SelectListItem                 {                     Value = ((int)item).ToString(),                     Text = title,                     Selected = selectedItem == ((int)item).ToString()                 };             items.Add(listItem);         }          return new SelectList(items, "Value", "Text", selectedItem);     } } 

Use it as:

Html.EnumDropDownListFor(m => m.YourEnum); 

Update

I've created alternative Html Helpers. All you need to do to use them is to change your baseviewpage in views\web.config.

With them you can just do:

@Html2.DropDownFor(m => m.YourEnum); @Html2.CheckboxesFor(m => m.YourEnum); @Html2.RadioButtonsFor(m => m.YourEnum); 

More info here: http://blog.gauffin.org/2011/10/first-draft-of-my-alternative-html-helpers/