C＃：枚举反模式 [英] C#: Enum anti-patterns

问题描述

已经有一般违反清洁code-原则通话枚举的，所以我要找的人最喜欢的枚举反模式和替代解决方案的这些。

There has been talk of Enums in general violating Clean Code-principles, so I'm looking for people's favorite Enum anti-patterns and alternative solutions for these.

例如我见过code是这样的：

For example I've seen code like this:

switch(enumValue) {
    case myEnum.Value1:
        // ...
        break;
    case myEnum.Value2:
        // ...
        break;
}

这是一步好于开关语句与魔术的字符串，但是这可能是本来可以更好地解决了工厂，容器或其它图案。

It's one step better than switch-statements with magic strings, but this probably could have been solved better with a factory, a container or other pattern.

甚至老派code是这样的：

Or even old-school code like this:

if(enumValue == myEnum.Value1) {
   // ...
} else if (enumValue == myEnum.Value2) {
   // ...
}

什么其他的反模式，更好的实现有你经历了枚举

推荐答案

我觉得枚举是非常有用的。我已经写了增加了更多的价值，以将其用于枚举了一些扩展

I think Enums are quite useful. I've written a few extensions for Enum that have added even more value to its use

首先，有描述扩展方法

public static class EnumExtensions
{
    public static string Description(this Enum value)
    {
        var entries = value.ToString().Split(ENUM_SEPERATOR_CHARACTER);
        var description = new string[entries.Length];
        for (var i = 0; i < entries.Length; i++)
        {
            var fieldInfo = value.GetType().GetField(entries[i].Trim());
            var attributes = (DescriptionAttribute[])fieldInfo.GetCustomAttributes(typeof(DescriptionAttribute), false);
            description[i] = (attributes.Length > 0) ? attributes[0].Description : entries[i].Trim();
        }
        return String.Join(", ", description);
    }
    private const char ENUM_SEPERATOR_CHARACTER = ',';
}

这将让我定义的连接枚举是这样的：

This will allow me to define en enum like this:

 public enum MeasurementUnitType
 {
    [Description("px")]
    Pixels = 0,
    [Description("em")]
    Em = 1,
    [Description("%")]
    Percent = 2,
    [Description("pt")]
    Points = 3
 }

和通过执行此操作获取标签： VAR myLabel = rectangle.widthunit.Description（）（无需任何一个开关语句）。

And get the label by doing this: var myLabel = rectangle.widthunit.Description() (eliminating any need for a switch statement).

这将BTW返回PX如果 rectangle.widthunit = MeasurementUnitType.Pixels ，否则将会返回PX，EM如果 rectangle.widthunit = MeasurementUnitType.Pixels | MeasurementUnitType.Em 。

This will btw return "px" if rectangle.widthunit = MeasurementUnitType.Pixels or it will return "px,em" if rectangle.widthunit = MeasurementUnitType.Pixels | MeasurementUnitType.Em.

然后，有一

    public static IEnumerable<int> GetIntBasedEnumMembers(Type @enum)
    {
        foreach (FieldInfo fi in @enum.GetFields(BindingFlags.Public | BindingFlags.Static))
            yield return (int)fi.GetRawConstantValue();
    }

这将让我穿越为int基于价值观的任何枚举，并返回整型值本身。

Which will let me traverse any enum with int based values and return the int values themselves.

我觉得这些是在一个媒体链接有用的概念非常有用。

I find these to be very useful in an allready useful concept.

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