枚举类型转换成字符串

使用枚举类型默认的ToString()方法，往往不能得到我们想要的输出的字符串。
如何方便的定义枚举类型中的每个值代表的字符串输出呢？
可以使用DescriptionAttribute, 写上想得到的字符串输出。

enum Direction
{
    [Description("Rover is facing to UP (Negtive Y)")]
    UP = 1,
    [Description("Rover is facing to DOWN (Positive Y)")]
    DOWN = 2,
    [Description("Rover is facing to RIGHT (Positive X)")]
    RIGHT = 3,
    [Description("Rover is facing to LEFT (Negtive X)")]
    LEFT = 4
}; 

使用下面的方法，来得到对应项的字符串。

/// <summary>
    /// Contains methods for working with <see cref="Enum"/>.
    /// </summary>
    public static class EnumHelper
    {
        /// <summary>
        /// Gets the specified enum value's description.
        /// </summary>
        /// <param name="value">The enum value.</param>
        /// <returns>The description or <c>null</c>
        /// if enum value doesn't have <see cref="DescriptionAttribute"/>.</returns>
        public static string GetDescription(this Enum value)
        {
            var fieldInfo = value.GetType().GetField(value.ToString());
            var attributes = (DescriptionAttribute[])fieldInfo.GetCustomAttributes(
                                                         typeof(DescriptionAttribute),
                                                         false);
            return attributes.Length > 0
                       ? attributes[0].Description
                       : null;
        }

        /// <summary>
        /// Gets the enum value by description.
        /// </summary>
        /// <typeparam name="EnumType">The enum type.</typeparam>
        /// <param name="description">The description.</param>
        /// <returns>The enum value.</returns>
        public static EnumType GetValueByDescription<EnumType>(string description)
        {
            var type = typeof(EnumType);
            if (!type.IsEnum)
                throw new ArgumentException("This method is destinated for enum types only.");
            foreach (var enumName in Enum.GetNames(type))
            {
                var enumValue = Enum.Parse(type, enumName);
                if (description == ((Enum)enumValue).GetDescription())
                    return (EnumType)enumValue;
            }
            throw new ArgumentException("There is no value with this description among specified enum type values.");
        }
    }

 进一步了解.net中的Attribue