Exclude/Remove Value from MVC 5.1 EnumDropDownListFor

Question

I have a list of enums that I am using for a user management page. I'm using the new HtmlHelper in MVC 5.1 that allows me to create a dropdown list for Enum values. I now have a need to remove the Pending value from the list, this value will only ever be set programatically and should never be set by the user.

Enum:

public enum UserStatus {     Pending = 0,     Limited = 1,     Active = 2 } 

View:

@Html.EnumDropDownListFor(model => model.Status) 

Is there anyway, either overriding the current control, or writing a custom HtmlHelper that would allow me to specify an enum, or enums to exclude from the resulting list? Or would you suggest I do something client side with jQuery to remove the value from the dropdown list once it has been generated?

Thanks!

Answer 1

You could construct a drop down list:

@{ // you can put the following in a back-end method and pass through ViewBag    var selectList = Enum.GetValues(typeof(UserStatus))                         .Cast<UserStatus>()                         .Where(e => e != UserStatus.Pending)                         .Select(e => new SelectListItem                              {                                  Value = ((int)e).ToString(),                                 Text = e.ToString()                             }); } @Html.DropDownListFor(m => m.Status, selectList) 

Answer 2

Modified from @dav_i's answer.

This is not perfect, but it is what I am using. Below is an extension to HtmlHelper. The extension method will look like EnumDropDownListFor from ASP.NET, and use DisplayAttribute if there is any applied to the Enum value.

/// <summary> /// Returns an HTML select element for each value in the enumeration that is /// represented by the specified expression and predicate. /// </summary> /// <typeparam name="TModel">The type of the model.</typeparam> /// <typeparam name="TEnum">The type of the value.</typeparam> /// <param name="htmlHelper">The HTML helper instance that this method extends.</param> /// <param name="expression">An expression that identifies the object that contains the properties to display.</param> /// <param name="optionLabel">The text for a default empty item. This parameter can be null.</param> /// <param name="predicate">A <see cref="Func{TEnum, bool}"/> to filter the items in the enums.</param> /// <param name="htmlAttributes">An object that contains the HTML attributes to set for the element.</param> /// <returns>An HTML select element for each value in the enumeration that is represented by the expression and the predicate.</returns> /// <exception cref="ArgumentNullException">If expression is null.</exception> /// <exception cref="ArgumentException">If TEnum is not Enum Type.</exception> public static MvcHtmlString EnumDropDownListFor<TModel, TEnum>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TEnum>> expression, Func<TEnum, bool> predicate, string optionLabel, object htmlAttributes) where TEnum : struct, IConvertible {     if (expression == null)     {         throw new ArgumentNullException("expression");     }      if (!typeof(TEnum).IsEnum)     {         throw new ArgumentException("TEnum");     }          IList<SelectListItem> selectList = Enum.GetValues(typeof(TEnum))             .Cast<TEnum>()             .Where(e => predicate(e))             .Select(e => new SelectListItem                 {                     Value = Convert.ToUInt64(e).ToString(),                     Text = ((Enum)(object)e).GetDisplayName(),                 }).ToList();     if (!string.IsNullOrEmpty(optionLabel)) {         selectList.Insert(0, new SelectListItem {             Text = optionLabel,         });     }      return htmlHelper.DropDownListFor(expression, selectList, htmlAttributes); }  /// <summary> /// Gets the name in <see cref="DisplayAttribute"/> of the Enum. /// </summary> /// <param name="enumeration">A <see cref="Enum"/> that the method is extended to.</param> /// <returns>A name string in the <see cref="DisplayAttribute"/> of the Enum.</returns> public static string GetDisplayName(this Enum enumeration) {     Type enumType = enumeration.GetType();     string enumName = Enum.GetName(enumType, enumeration);     string displayName = enumName;     try     {         MemberInfo member = enumType.GetMember(enumName)[0];          object[] attributes = member.GetCustomAttributes(typeof(DisplayAttribute), false);         DisplayAttribute attribute = (DisplayAttribute)attributes[0];         displayName = attribute.Name;          if (attribute.ResourceType != null)         {             displayName = attribute.GetName();         }     }     catch { }     return displayName; } 

For example:

@Html.EnumDropDownListFor(     model => model.UserStatus,     (userStatus) => { return userStatus != UserStatus.Active; },     null,     htmlAttributes: new { @class = "form-control" }) 

This will create an Enum dropdown list without the the option of Active.