enum 的轉換

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下面範例列出 enum 對 int、string 型別的互轉，與取 Description 描述名稱的方式。

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// int to enum
using System.ComponentModel;
using System.Reflection;

Console.WriteLine((DayOfWork)0); // output:Sunday
Console.WriteLine();

// enum to int
Console.WriteLine((int)DayOfWork.Monday); // output:1
Console.WriteLine();

// enum to string
Console.WriteLine(DayOfWork.Tuesday.ToString()); // output:Tuesday
Console.WriteLine();

// string to enum
Console.WriteLine(Enum.Parse(typeof(DayOfWork), "Wednesday")); // output:Wednesday
Console.WriteLine();

// 取 Description 描述名稱
Console.WriteLine(GetDescriptionText(DayOfWork.Thursday)); // output:星期四
Console.WriteLine();

// 列出 enum DayOfWork 所有名稱
foreach (string en in Enum.GetNames(typeof(DayOfWork)))
    Console.WriteLine(en);
Console.WriteLine();
// output:
// Sunday
// Monday
// Tuesday
// Wednesday
// Thursday
// Friday
// Saturday

// 列出 enum DayOfWork 所有值
foreach (int v in Enum.GetValues(typeof(DayOfWork)))
    Console.WriteLine(v);
Console.WriteLine();
// output:
// 0
// 1
// 2
// 3
// 4
// 5
// 6

string GetDescriptionText(Enum source)
{
    FieldInfo fi = source.GetType().GetField(source.ToString());
    DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
    if (attributes.Length > 0)
        return attributes[0].Description;
    else
        return source.ToString();
}

enum DayOfWork
{
    [Description("星期日")]
    Sunday = 0,

    [Description("星期一")]
    Monday = 1,

    [Description("星期二")]
    Tuesday = 2,

    [Description("星期三")]
    Wednesday = 3,

    [Description("星期四")]
    Thursday = 4,

    [Description("星期五")]
    Friday = 5,

    [Description("星期六")]
    Saturday = 6
}