关于Enum和DataAnnotation [英] About Enum and DataAnnotation

问题描述

我有这个枚举（Notebook.cs）：

I have this Enum (Notebook.cs):

public enum Notebook : byte
{
   [Display(Name = "Notebook HP")]
   NotebookHP,

   [Display(Name = "Notebook Dell")]
   NotebookDell
}

此类中的此属性（TIDepartment.cs）：

Also this property in my class (TIDepartment.cs):

public Notebook Notebook { get; set; }

它的工作完美，我只有一个问题：

It's working perfectly, I just have one "problem":

我创建了一个EnumDDLFor，它显示了在DisplayAttribute中设置的名称，带有空格，但该对象在DisplayAttribute中没有收到该名称，接收到Enum名称（正确的是），所以我的问题是：

I created an EnumDDLFor and it's showing the name I setted in DisplayAttribute, with spaces, but the object doesn't receive that name in DisplayAttribute, receives the Enum name (what is correct), so my question is:

有没有办法使用DisplayAttribute中配置的空格接收名称？

Is there a way to receive the name with spaces which one I configured in DisplayAttribute?

推荐答案

MVC不会使用枚举上的Display属性（或任何我知道的框架）。您需要创建一个自定义的枚举扩展类：

MVC doesn't make use of the Display attribute on enums (or any framework I'm aware of). You need to create a custom Enum extension class:

public static class EnumExtensions
{
    public static string GetDisplayAttributeFrom(this Enum enumValue, Type enumType)
    {
        string displayName = "";
        MemberInfo info = enumType.GetMember(enumValue.ToString()).First();

        if (info != null && info.CustomAttributes.Any())
        {
            DisplayAttribute nameAttr = info.GetCustomAttribute<DisplayAttribute>();
            displayName = nameAttr != null ? nameAttr.Name : enumValue.ToString();
        }
        else
        {
            displayName = enumValue.ToString();
        }
        return displayName;
    }
}

然后你可以这样使用：

Notebook n = Notebook.NotebookHP;
String displayName = n.GetDisplayAttributeFrom(typeof(Notebook));

编辑：支持本地化

这可能不是最有效的方式，但是应该工作。

This may not be the most efficient way, but SHOULD work.

public static class EnumExtensions
{
    public static string GetDisplayAttributeFrom(this Enum enumValue, Type enumType)
    {
        string displayName = "";
        MemberInfo info = enumType.GetMember(enumValue.ToString()).First();

        if (info != null && info.CustomAttributes.Any())
        {
            DisplayAttribute nameAttr = info.GetCustomAttribute<DisplayAttribute>();

            if(nameAttr != null) 
            {
                // Check for localization
                if(nameAttr.ResourceType != null && nameAttr.Name != null)
                {
                    // I recommend not newing this up every time for performance
                    // but rather use a global instance or pass one in
                    var manager = new ResourceManager(nameAttr.ResourceType);
                    displayName = manager.GetString(nameAttr.Name)
                }
                else if (nameAttr.Name != null)
                {
                    displayName = nameAttr != null ? nameAttr.Name : enumValue.ToString();
                }
            }
        }
        else
        {
            displayName = enumValue.ToString();
        }
        return displayName;
    }
}

在枚举中，密钥和资源类型必须为指定：

On the enum, the key and resource type must be specified:

[Display(Name = "MyResourceKey", ResourceType = typeof(MyResourceFile)]

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