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
假设你的枚举名称是OrderState，使用以下代码:
@Html.DropDownList("selectList", new SelectList(Html.GetEnumSelectList<OrderState>(), "Value", "Text",ViewBag.selectedOrderState), new {@id="OrderState", @class = "form-control" })
在后台设置选中的选项:
var selectedOrderState = ..Data.OrderState.GetHashCode();
ViewBag.selectedOrderState = selectedOrderState;
我很抱歉这样做，但我不能使用任何其他的答案，也没有时间在评论中争论。
使用c# 6语法。
static class EnumExtensions
{
/// returns the localized Name, if a [Display(Name="Localised Name")] attribute is applied to the enum member
/// returns null if there isnt an attribute
public static string DisplayNameOrEnumName(this Enum value)
// => value.DisplayNameOrDefault() ?? value.ToString()
{
// More efficient form of ^ based on http://stackoverflow.com/a/17034624/11635
var enumType = value.GetType();
var enumMemberName = Enum.GetName(enumType, value);
return enumType
.GetEnumMemberAttribute<DisplayAttribute>(enumMemberName)
?.GetName() // Potentially localized
?? enumMemberName; // Or fall back to the enum name
}
/// returns the localized Name, if a [Display] attribute is applied to the enum member
/// returns null if there is no attribute
public static string DisplayNameOrDefault(this Enum value) =>
value.GetEnumMemberAttribute<DisplayAttribute>()?.GetName();
static TAttribute GetEnumMemberAttribute<TAttribute>(this Enum value) where TAttribute : Attribute =>
value.GetType().GetEnumMemberAttribute<TAttribute>(value.ToString());
static TAttribute GetEnumMemberAttribute<TAttribute>(this Type enumType, string enumMemberName) where TAttribute : Attribute =>
enumType.GetMember(enumMemberName).Single().GetCustomAttribute<TAttribute>();
}
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
