枚举带有字符串值并通过值查找枚举 [英] Enums with string values and finding enum by value

问题描述

我想要一个像下面这样的枚举，然后有一个方法，如Util.FindFruitByValue（A），它返回枚举苹果。这是因为缩写存储在数据库中，我需要在从db读取数据之后将其转换为适当的枚举。这是可能OR还是需要为它创建一个单独的类？请告诉我。感谢提前。

  public enum Fruit 
 {
 Apple =A
香蕉=B
 Cherry =C
} 
  

更新：就像一个查找表，不同之处在于值是string而不是int。我正在填充一个业务对象，通过读取数据库中的值，我想使用一个具有固定值的对象属性而不是字符串的类型。

解决方案

我使用枚举中的描述属性解决了问题。解决方案如下。我使用扩展方法来获取描述。获取描述的代码取自此链接 http://blog.spontaneouspublicity.com/post/2008/01/17/Associating-Strings-with-enums-in-C.aspx 。感谢您的答复。

  public enum Fruit 
 {
 [Description（Apple）] 
 A，
 [描述（香蕉）] 
 B，
 [描述（樱桃）] 
 C 
} 
 
 public static class Util 
 {
 public static T StringToEnum< T>（string name）
 {
 return（T）Enum.Parse（typeof（T） ）; 
} 
 
 public static string ToDescriptionString（此枚举值）
 {
 FieldInfo fi = value.GetType（）。GetField（value.ToString（））; 
 
 DescriptionAttribute [] attributes = 
（DescriptionAttribute []）fi.GetCustomAttributes（
 typeof（DescriptionAttribute），
 false）; 
 
 if（attributes！= null&& 
 attributes.Length> 0）
返回属性[0] .Description; 
 else 
返回值.ToString（）; 
} 
} 
  

I want to have an enum like the following and then have a method something like Util.FindFruitByValue("A") which returns the enum Apple. this is because the abbreviations are stored in database and I need to convert them to appropriate enums after reading from db. is this possible OR do I need to create a separate class for it? Please let me know. thanks in advance.

public enum Fruit
{
    Apple = "A"
    Banana = "B"
    Cherry = "C"
}

Update: this is like a lookup table, but the difference is the value is string instead of an int. I am populating a business object, by reading the values from database and I would like to use a type with fixed values for the object property instead of string.

解决方案

I solved the problem by using the Description attribute on the enum. the solution is as follows. I use the extension method to get the description. the code to get the description is taken from this link http://blog.spontaneouspublicity.com/post/2008/01/17/Associating-Strings-with-enums-in-C.aspx. thanks for your replies.

    public enum Fruit
{
    [Description("Apple")]
    A,
    [Description("Banana")]
    B,
    [Description("Cherry")]
    C
}

public static class Util
{
    public static T StringToEnum<T>(string name)
    {
        return (T)Enum.Parse(typeof(T), name);
    }

    public static string ToDescriptionString(this Enum value)
    {
        FieldInfo fi = value.GetType().GetField(value.ToString());

        DescriptionAttribute[] attributes =
            (DescriptionAttribute[])fi.GetCustomAttributes(
            typeof(DescriptionAttribute),
            false);

        if (attributes != null &&
            attributes.Length > 0)
            return attributes[0].Description;
        else
            return value.ToString();
    }
}

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