我的枚举由以下值组成:

private enum PublishStatusses{
    NotCompleted,
    Completed,
    Error
};

我希望能够以用户友好的方式输出这些值。 我不需要再从字符串到值。


当前回答

不要使用枚举,使用静态类。

取代

private enum PublishStatuses{
    NotCompleted,
    Completed,
    Error
};

with

private static class PublishStatuses{
    public static readonly string NotCompleted = "Not Completed";
    public static readonly string Completed = "Completed";
    public static readonly string Error = "Error";
};

它是这样使用的

PublishStatuses.NotCompleted; // "Not Completed"

使用顶级“扩展方法”解决方案的问题:

私有枚举通常在另一个类中使用。扩展方法解决方案在那里无效,因为它必须在它自己的类中。这个解决方案可以是私有的,并嵌入到另一个类中。

其他回答

我使用系统中的Description属性。ComponentModel名称空间。简单地装饰enum:

private enum PublishStatusValue
{
    [Description("Not Completed")]
    NotCompleted,
    Completed,
    Error
};

然后使用下面的代码来检索它:

public static string GetDescription<T>(this T enumerationValue)
    where T : struct
{
    Type type = enumerationValue.GetType();
    if (!type.IsEnum)
    {
        throw new ArgumentException("EnumerationValue must be of Enum type", "enumerationValue");
    }

    //Tries to find a DescriptionAttribute for a potential friendly name
    //for the enum
    MemberInfo[] memberInfo = type.GetMember(enumerationValue.ToString());
    if (memberInfo != null && memberInfo.Length > 0)
    {
        object[] attrs = memberInfo[0].GetCustomAttributes(typeof(DescriptionAttribute), false);

        if (attrs != null && attrs.Length > 0)
        {
            //Pull out the description value
            return ((DescriptionAttribute)attrs[0]).Description;
        }
    }
    //If we have no description attribute, just return the ToString of the enum
    return enumerationValue.ToString();
}
public enum MyEnum
{
    [Description("Option One")]
    Option_One
}

public static string ToDescriptionString(this Enum This)
{
    Type type = This.GetType();

    string name = Enum.GetName(type, This);

    MemberInfo member = type.GetMembers()
        .Where(w => w.Name == name)
        .FirstOrDefault();

    DescriptionAttribute attribute = member != null
        ? member.GetCustomAttributes(true)
            .Where(w => w.GetType() == typeof(DescriptionAttribute))
            .FirstOrDefault() as DescriptionAttribute
        : null;

    return attribute != null ? attribute.Description : name;
}

我使用一个泛型类来存储枚举/描述对,并使用一个嵌套的helper类来获取描述。

枚举:

enum Status { Success, Fail, Pending }

泛型类:

注意:由于泛型类不能被枚举约束,我用struct来代替约束,并在构造函数中检查enum。

public class EnumX<T> where T : struct
{
    public T Code { get; set; }
    public string Description { get; set; }

    public EnumX(T code, string desc)
    {
        if (!typeof(T).IsEnum) throw new NotImplementedException();

        Code = code;
        Description = desc;
    }

    public class Helper
    {
        private List<EnumX<T>> codes;

        public Helper(List<EnumX<T>> codes)
        {
            this.codes = codes;
        }

        public string GetDescription(T code)
        {
            EnumX<T> e = codes.Where(c => c.Code.Equals(code)).FirstOrDefault();
            return e is null ? "Undefined" : e.Description;
        }
    }
}

用法:

EnumX<Status>.Helper StatusCodes = new EnumX<Status>.Helper(new List<EnumX<Status>>()
        {
            new EnumX<Status>(Status.Success,"Operation was successful"),
            new EnumX<Status>(Status.Fail,"Operation failed"),
            new EnumX<Status>(Status.Pending,"Operation not complete. Please wait...")
        });

        Console.WriteLine(StatusCodes.GetDescription(Status.Pending));

其他一些避免类/引用类型的更基本的选项:

数组的方法 嵌套结构方法

数组的方法

private struct PublishStatusses
{
    public static string[] Desc = {
        "Not Completed",
        "Completed",
        "Error"
    };

    public enum Id
    {
        NotCompleted = 0,
        Completed,
        Error
    };
}

使用

string desc = PublishStatusses.Desc[(int)PublishStatusses.Id.Completed];

嵌套结构方法

private struct PublishStatusses
{
    public struct NotCompleted
    {
        public const int Id = 0;
        public const string Desc = "Not Completed";
    }

    public struct Completed
    {
        public const int Id = 1;
        public const string Desc = "Completed";
    }

    public struct Error
    {
        public const int Id = 2;
        public const string Desc = "Error";
    }            
}

使用

int id = PublishStatusses.NotCompleted.Id;
string desc = PublishStatusses.NotCompleted.Desc;

更新(03/09/2018)

扩展方法和上面第一种技术的混合。

我更喜欢将枚举定义在它们“所属”的位置(最接近它们的起源源,而不是某个通用的全局名称空间)。

namespace ViewModels
{
    public class RecordVM
    {
        //public enum Enum { Minutes, Hours }
        public struct Enum
        {
            public enum Id { Minutes, Hours }
            public static string[] Name = { "Minute(s)", "Hour(s)" };
        }
    }
}

扩展方法似乎适合于公共区域,枚举的“本地化”定义现在使扩展方法更加详细。

namespace Common
{
    public static class EnumExtensions
    {
        public static string Name(this RecordVM.Enum.Id id)
        {
            return RecordVM.Enum.Name[(int)id];
        }
    }   
}

枚举及其扩展方法的使用示例。

namespace Views
{
    public class RecordView 
    {
        private RecordDataFieldList<string, string> _fieldUnit;

        public RecordView()
        {
            _fieldUnit.List = new IdValueList<string, string>
            {            
                new ListItem<string>((int)RecordVM.Enum.Id.Minutes, RecordVM.Enum.Id.Minutes.Name()),
                new ListItem<string>((int)RecordVM.Enum.Id.Hours, RecordVM.Enum.Id.Hours.Name())
            };
        }

        private void Update()
        {    
            RecordVM.Enum.Id eId = DetermineUnit();

            _fieldUnit.Input.Text = _fieldUnit.List.SetSelected((int)eId).Value;
        }
    }
}

注意:我实际上决定消除Enum包装器(和Name数组),因为名称字符串最好来自资源(即配置文件或DB)而不是硬编码,并且因为我最终将扩展方法放在ViewModels名称空间中(只是在不同的“CommonVM.cs”文件中)。此外,整个。id的事情变得令人分心和麻烦。

namespace ViewModels
{
    public class RecordVM
    {
        public enum Enum { Minutes, Hours }
        //public struct Enum
        //{
        //    public enum Id { Minutes, Hours }
        //    public static string[] Name = { "Minute(s)", "Hour(s)" };
        //}
    }
}

CommonVM.cs

//namespace Common
namespace ViewModels
{
    public static class EnumExtensions
    {
        public static string Name(this RecordVM.Enum id)
        {
            //return RecordVM.Enum.Name[(int)id];
            switch (id)
            {
                case RecordVM.Enum.Minutes: return "Minute(s)";                    
                case RecordVM.Enum.Hours: return "Hour(s)";
                default: return null;
            }
        }
    }   
}

枚举及其扩展方法的使用示例。

namespace Views
{
    public class RecordView 
    {
        private RecordDataFieldList<string, string> _fieldUnit

        public RecordView()
        {
            _fieldUnit.List = new IdValueList<string, string>
            {            
                new ListItem<string>((int)RecordVM.Enum.Id.Minutes, RecordVM.Enum.Id.Minutes.Name()),
                new ListItem<string>((int)RecordVM.Enum.Id.Hours, RecordVM.Enum.Id.Hours.Name())
            };
        }

        private void Update()
        {    
            RecordVM.Enum eId = DetermineUnit();

            _fieldUnit.Input.Text = _fieldUnit.List.SetSelected((int)eId).Value;
        }
    }
}

我用扩展方法做到这一点:

public enum ErrorLevel
{
  None,
  Low,
  High,
  SoylentGreen
}

public static class ErrorLevelExtensions
{
  public static string ToFriendlyString(this ErrorLevel me)
  {
    switch(me)
    {
      case ErrorLevel.None:
        return "Everything is OK";
      case ErrorLevel.Low:
        return "SNAFU, if you know what I mean.";
      case ErrorLevel.High:
        return "Reaching TARFU levels";
      case ErrorLevel.SoylentGreen:
        return "ITS PEOPLE!!!!";
      default:
        return "Get your damn dirty hands off me you FILTHY APE!";
    }
  }
}