如何避免在同一范围内多次重复输入相同的名称？

Question

我有以下enum：

public enum Event0Instance
{
    ClaimSent,
    RequestSent,
    ClaimResponseAqcuired,
    RequestResponseAqcuired,
    RequestRefusalAcquired,
}

有了这个enum，我制作了字典 Dictionary<Event0Instance, string>，其中string 值是每个枚举值的文本描述：

public static Dictionary<Event0Instance, string> Event0Descriptions = 
  new Dictionary<Event0Instance, string>() 
  {
    {Event0Instance.ClaimSent, "Подана претензия" },
    {Event0Instance.RequestSent, "Подан запрос"},
    {Event0Instance.ClaimResponseAqcuired, "Получен ответ на претензию"},
    {Event0Instance.RequestResponseAqcuired, "Получен ответ на запрос"},
    {Event0Instance.RequestRefusalAcquired, "Получен отказ на запрос"}
  };

这里明显的问题是需要对每个条目重复 Event0Instance.。有 更多 enums，每个 比示例中的更大，如果我想为每个人创建一个 Dictionary，这是一个 巨大的代码重复.

在 VBA 语言中有一个 With / End Withconstruct 你可以这样使用：

With Person
    .FirstName = "John"
    .LastName = "Smith"
    .Age = 23
End With

C#中是否有类似的东西？

Answer 1

为了跳过讨厌的Event0Instance.前缀，你可以试试using static构造，它的工作原理与with .. end with大致相似：

using static MyNamespace.Event0Instance;

...

public static Dictionary<Event0Instance, string> Event0Descriptions =
  new Dictionary<Event0Instance, string>() 
  {
    {ClaimSent, "Подана претензия" },
    {RequestSent, "Подан запрос"},
    {ClaimResponseAqcuired, "Получен ответ на претензию"},
    {RequestResponseAqcuired, "Получен ответ на запрос"},
    {RequestRefusalAcquired, "Получен отказ на запрос"}
  };

但是，我建议使用 attributes 并在 Linq 和 Reflection 的帮助下构建字典：

// Here we attribute each option with the desired description
public enum Event0Instance
{
    //TODO: do not hardcode the descriptions ("Подана претензия") 
    // but put resource name here
    [Description("Подана претензия")]
    ClaimSent,
    [Description("Подан запрос")]
    RequestSent,
    [Description("Получен ответ на претензию")]
    ClaimResponseAqcuired,
    [Description("Получен ответ на запрос")]
    RequestResponseAqcuired,
    [Description("Получен отказ на запрос")]
    RequestRefusalAcquired,
}

这是检查给定枚举并返回 {option, description} 字典的例程：

using System.Linq;
using System.Reflection;

...

// This routine inspects the enum given and return dictionary: {option, description} 
public static Dictionary<T, string> EnumDescriptions<T>() where T : Enum {
  return Enum
    .GetNames(typeof(T))
    .Select(name => new {
      name,
      value = Enum.Parse(typeof(T), name),
      member = typeof(T).GetMember(name)[0]
    })
    .ToDictionary(item => (T) (item.value),
                  item => item.member
                    .GetCustomAttributes<DescriptionAttribute>(true)
                    .FirstOrDefault()?.Description ?? item.name);
}

然后您可以在一行代码中构建字典：

// I doubt if you want public (!) Dictionary exposed to everyone;
// I guess readonly interface will be enough
public static readonly IReadOnlyDictionary<Event0Instance, string> Event0Descriptions = 
  EnumDescriptions<Event0Instance>();