TIPS-Conversion Between enum, int And string

2007-06-28 02:48 PM

.NET中的Enumerate可以提高程式的嚴謹性及可讀性，我最愛的一個例子是DateTime的DayOfWork Enumeration。

if (DateTime.Now.DayOfWeek==DayOfWeek.Friday)是不是比DateTime.Now.DayOfWeek==5更容易閱讀呢? 而當要求使用者傳入星期幾作為參數時，也不必擔心User傳入-1 或18來搗蛋。

不過，在某些時候，我們還是需要將星期三轉成數字3，或是將"Sunday"解讀成為DayOfWeek.Sunday。廢話不多說，請大家看以下的程式，它完整地示範了如何進行int<->enum, string<->enum間的轉換:

int i = 3;

//Convert From Integer to Enum

DayOfWeek dw = (DayOfWeek)Enum.ToObject(typeof(DayOfWeek), i);

Console.WriteLine(string.Format("int [{0}] -> enum [{1}]", i, dw));

//Convert From Enum To Integer

dw = DayOfWeek.Thursday;

i = (int)dw;

Console.WriteLine(string.Format("enum [{1}] -> int [{0}]", i, dw));

//Convert From Enum To String

dw = DayOfWeek.Friday;

string s = dw.ToString();

Console.WriteLine(string.Format("enum [{1}] -> string '{0}'", s, dw));

//Convert From String To Enum

s = "Sunday";

dw = (DayOfWeek)Enum.Parse(typeof(DayOfWeek), s);

Console.WriteLine(string.Format("string '{0}' -> enum [{1}]", s, dw));

執行結果如下:

int [3] -> enum [Wednesday]
enum [Thursday] -> int [4]
enum [Friday] -> string 'Friday'
string 'Sunday' -> enum [Sunday]

Comments