c# - 列挙型メンバーから DescriptionAttribute 値を取得する方法

Question

私は列挙型を持っています

public enum DataType:int
    {   
        None = 0,
        [Description("A")]
        Alpha = 1,
        [Description("N")]
        Numeric,
        [Description("AN")]
        AlphaNumeric,
        [Description("D")]
        Date
    }

たとえば、アルファの説明属性値を取得するにはどうすればよいですか。

例（理想）：「A」DataType.Alpha.Attributeを与えるべきです

Answer 1

これを使って

private string GetEnumDescription(Enum value)
{
    // Get the Description attribute value for the enum value
    FieldInfo fi = value.GetType().GetField(value.ToString());
    DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);

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

Answer 2

私はまさにそれを行うための拡張メソッドを持っています：

public static string GetDescription(this Enum enumValue)
    {
        //Look for DescriptionAttributes on the enum field
        object[] attr = enumValue.GetType().GetField(enumValue.ToString())
            .GetCustomAttributes(typeof (DescriptionAttribute), false);

        if (attr.Length > 0) // a DescriptionAttribute exists; use it
            return ((DescriptionAttribute) attr[0]).Description;

        //The above code is all you need if you always use DescriptionAttributes;
        //If you don't, the below code will semi-intelligently 
        //"humanize" an UpperCamelCased Enum identifier
        string result = enumValue.ToString();

        //"FooBar" -> "Foo Bar"
        result = Regex.Replace(result, @"([a-z])([A-Z])", "$1 $2");

        //"Foo123" -> "Foo 123"
        result = Regex.Replace(result, @"([A-Za-z])([0-9])", "$1 $2");

        //"123Foo" -> "123 Foo"
        result = Regex.Replace(result, @"([0-9])([A-Za-z])", "$1 $2");

        //"FOOBar" -> "FOO Bar"
        result = Regex.Replace(result, @"(?<!^)(?<! )([A-Z][a-z])", " $1");

        return result;
    }

使用法：

var description = DataType.Alpha.GetDescription(); //"A"

public enum TestEnums
{
   IAmAComplexABCEnumValue,
}

//"I Am A Complex ABC Enum Value"
var complexCamelCasedDescription = TestEnums.IAmAComplexABCEnumValue.GetDescription();