我在我的模型中有一个属性叫做Promotion,它的类型是一个标志enum叫做UserPromotion。枚举成员的显示属性设置如下:
[Flags]
public enum UserPromotion
{
None = 0x0,
[Display(Name = "Send Job Offers By Mail")]
SendJobOffersByMail = 0x1,
[Display(Name = "Send Job Offers By Sms")]
SendJobOffersBySms = 0x2,
[Display(Name = "Send Other Stuff By Sms")]
SendPromotionalBySms = 0x4,
[Display(Name = "Send Other Stuff By Mail")]
SendPromotionalByMail = 0x8
}
现在我想要能够在我的视图中创建一个ul来显示我的Promotion属性的选定值。这就是我到目前为止所做的但问题是,我如何在这里获得显示名称?
<ul>
@foreach (int aPromotion in @Enum.GetValues(typeof(UserPromotion)))
{
var currentPromotion = (int)Model.JobSeeker.Promotion;
if ((currentPromotion & aPromotion) == aPromotion)
{
<li>Here I don't know how to get the display attribute of "currentPromotion".</li>
}
}
</ul>
在Aydin和Todd回答的基础上,下面是一个扩展方法,它还可以让您从资源文件中获得名称
using AppResources;
using System;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
using System.Resources;
public static class EnumExtensions
{
public static string GetDisplayName(this Enum enumValue)
{
var enumMember= enumValue.GetType()
.GetMember(enumValue.ToString());
DisplayAttribute displayAttrib = null;
if (enumMember.Any()) {
displayAttrib = enumMember
.First()
.GetCustomAttribute<DisplayAttribute>();
}
string name = null;
Type resource = null;
if (displayAttrib != null)
{
name = displayAttrib.Name;
resource = displayAttrib.ResourceType;
}
return String.IsNullOrEmpty(name) ? enumValue.ToString()
: resource == null ? name
: new ResourceManager(resource).GetString(name);
}
}
然后像这样使用它
public enum Season
{
[Display(ResourceType = typeof(Resource), Name = Season_Summer")]
Summer
}
对于这个问题,我有两个解决方案。
第一个解决方案是从enum中获取显示名称。
public enum CourseLocationTypes
{
[Display(Name = "On Campus")]
OnCampus,
[Display(Name = "Online")]
Online,
[Display(Name = "Both")]
Both
}
public static string DisplayName(this Enum value)
{
Type enumType = value.GetType();
string enumValue = Enum.GetName(enumType, value);
MemberInfo member = enumType.GetMember(enumValue)[0];
object[] attrs = member.GetCustomAttributes(typeof(DisplayAttribute), false);
string outString = ((DisplayAttribute)attrs[0]).Name;
if (((DisplayAttribute)attrs[0]).ResourceType != null)
{
outString = ((DisplayAttribute)attrs[0]).GetName();
}
return outString;
}
<h3 class="product-title white">@Model.CourseLocationType.DisplayName()</h3>
第二个解决方案是从枚举名称中获取显示名称,但在开发人员语言中它被称为patch。
public static string SplitOnCapitals(this string text)
{
var r = new Regex(@"
(?<=[A-Z])(?=[A-Z][a-z]) |
(?<=[^A-Z])(?=[A-Z]) |
(?<=[A-Za-z])(?=[^A-Za-z])", RegexOptions.IgnorePatternWhitespace);
return r.Replace(text, " ");
}
<div class="widget-box pt-0">
@foreach (var item in Enum.GetNames(typeof(CourseLocationType)))
{
<label class="pr-2 pt-1">
@Html.RadioButtonFor(x => x.CourseLocationType, item, new { type = "radio", @class = "iCheckBox control-label" }) @item.SplitOnCapitals()
</label>
}
@Html.ValidationMessageFor(x => x.CourseLocationType)
</div>
我试着把它作为一个编辑,但它被拒绝了;我不明白为什么。
如果你用一个混合了自定义属性和普通项的Enum调用它,上面的方法会抛出一个异常。
public enum CommentType
{
All = 1,
Rent = 2,
Insurance = 3,
[Display(Name="Service Charge")]
ServiceCharge = 4
}
因此,我稍微修改了代码,以便在尝试访问自定义属性之前检查它们,如果没有找到则使用名称。
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
public static class EnumHelper<T>
{
public static IList<T> GetValues(Enum value)
{
var enumValues = new List<T>();
foreach (FieldInfo fi in value.GetType().GetFields(BindingFlags.Static | BindingFlags.Public))
{
enumValues.Add((T)Enum.Parse(value.GetType(), fi.Name, false));
}
return enumValues;
}
public static T Parse(string value)
{
return (T)Enum.Parse(typeof(T), value, true);
}
public static IList<string> GetNames(Enum value)
{
return value.GetType().GetFields(BindingFlags.Static | BindingFlags.Public).Select(fi => fi.Name).ToList();
}
public static IList<string> GetDisplayValues(Enum value)
{
return GetNames(value).Select(obj => GetDisplayValue(Parse(obj))).ToList();
}
private static string lookupResource(Type resourceManagerProvider, string resourceKey)
{
foreach (PropertyInfo staticProperty in resourceManagerProvider.GetProperties(BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public))
{
if (staticProperty.PropertyType == typeof(System.Resources.ResourceManager))
{
System.Resources.ResourceManager resourceManager = (System.Resources.ResourceManager)staticProperty.GetValue(null, null);
return resourceManager.GetString(resourceKey);
}
}
return resourceKey; // Fallback with the key name
}
public static string GetDisplayValue(T value)
{
var fieldInfo = value.GetType().GetField(value.ToString());
var descriptionAttributes = fieldInfo.GetCustomAttributes(
typeof(DisplayAttribute), false) as DisplayAttribute[];
if (descriptionAttributes.Any() && descriptionAttributes[0].ResourceType != null)
return lookupResource(descriptionAttributes[0].ResourceType, descriptionAttributes[0].Name);
if (descriptionAttributes == null) return string.Empty;
return (descriptionAttributes.Length > 0) ? descriptionAttributes[0].Name : value.ToString();
}
}