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>
一行-流畅的语法
public static class Extensions
{
/// <summary>
/// A generic extension method that aids in reflecting
/// and retrieving any attribute that is applied to an `Enum`.
/// </summary>
public static TAttribute GetAttribute<TAttribute>(this Enum enumValue)
where TAttribute : Attribute
{
return enumValue.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<TAttribute>();
}
}
例子
public enum Season
{
[Display(Name = "It's autumn")]
Autumn,
[Display(Name = "It's winter")]
Winter,
[Display(Name = "It's spring")]
Spring,
[Display(Name = "It's summer")]
Summer
}
public class Foo
{
public Season Season = Season.Summer;
public void DisplayName()
{
var seasonDisplayName = Season.GetAttribute<DisplayAttribute>();
Console.WriteLine("Which season is it?");
Console.WriteLine (seasonDisplayName.Name);
}
}
输出
现在是哪个季节?
现在是夏天
从上面将所有边情况组合在一起:
枚举包含基对象成员名的成员(Equals, ToString)
可选显示属性
这是我的代码:
public enum Enum
{
[Display(Name = "What a weird name!")]
ToString,
Equals
}
public static class EnumHelpers
{
public static string GetDisplayName(this Enum enumValue)
{
var enumType = enumValue.GetType();
return enumType
.GetMember(enumValue.ToString())
.Where(x => x.MemberType == MemberTypes.Field && ((FieldInfo)x).FieldType == enumType)
.First()
.GetCustomAttribute<DisplayAttribute>()?.Name ?? enumValue.ToString();
}
}
void Main()
{
Assert.Equals("What a weird name!", Enum.ToString.GetDisplayName());
Assert.Equals("Equals", Enum.Equals.GetDisplayName());
}
基于Aydin的回答，这里有一个不需要任何类型参数的扩展方法。
using System;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
public static class EnumExtensions
{
public static string GetDisplayName(this Enum enumValue)
{
return enumValue.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>()
.GetName();
}
}
注意:应该使用GetName()而不是Name属性。这确保如果使用ResourceType属性，将返回本地化的字符串。
例子
要使用它，只需在视图中引用枚举值。
@{
UserPromotion promo = UserPromotion.SendJobOffersByMail;
}
Promotion: @promo.GetDisplayName()
输出
促销:通过邮件发送工作邀请
我想贡献与区域性相关的GetDisplayName enum扩展。希望这对以前像我一样在谷歌上搜索这个答案的人有用:
Aydin Adn和Todd提到的“标准”方式:
public static string GetDisplayName(this Enum enumValue)
{
return enumValue
.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>()
.GetName();
}
“文化相关的”方式:
public static string GetDisplayName(this Enum enumValue, CultureInfo ci)
{
var displayAttr = enumValue
.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>();
var resMan = displayAttr.ResourceType?.GetProperty(@"ResourceManager", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).GetValue(null, null) as ResourceManager;
return resMan?.GetString(displayAttr.Name, ci) ?? displayAttr.GetName();
}
一行-流畅的语法
public static class Extensions
{
/// <summary>
/// A generic extension method that aids in reflecting
/// and retrieving any attribute that is applied to an `Enum`.
/// </summary>
public static TAttribute GetAttribute<TAttribute>(this Enum enumValue)
where TAttribute : Attribute
{
return enumValue.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<TAttribute>();
}
}
例子
public enum Season
{
[Display(Name = "It's autumn")]
Autumn,
[Display(Name = "It's winter")]
Winter,
[Display(Name = "It's spring")]
Spring,
[Display(Name = "It's summer")]
Summer
}
public class Foo
{
public Season Season = Season.Summer;
public void DisplayName()
{
var seasonDisplayName = Season.GetAttribute<DisplayAttribute>();
Console.WriteLine("Which season is it?");
Console.WriteLine (seasonDisplayName.Name);
}
}
输出
现在是哪个季节?
现在是夏天
