为枚举(enum)类型添加的备注属性，并且获取枚举的属性值

 枚举类型（也称为枚举）是非常有意思的的一种值类型，它不仅可以提高程序的可读性，而且可以减少因业务改变而导致的程序改动。

 另外枚举类型是强类型，接受方法必须有一个相同的匹配参数，否则将会出错。

 好，废话少说，至于枚举类型(emun)的特性，几乎会编程的人都懂的，偶没功力在这里长篇大论。

 下面是一个例子，偶还是按官方的写法，以星期为例子：

 

代码

class Program
{
static void Main( string [] args)
{

Console.Write(GetDays(Days.Saturday));
Console.Read();
}

static string GetDays(Days _days)
{
string d = string .Empty;
switch (_days)
{
case Days.Monday: d = " Today is Monday. " ; break ;
case Days.Tuesday: d = " Today is Tuesday. " ; break ;
case Days.Wednesday: d = " Today is Wednesday. " ; break ;
case Days.Thursday: d = " Today is Thursday. " ; break ;
case Days.Friday: d = " Today is Friday. " ; break ; ;
case Days.Saturday: d = " Today is Saturday. " ; break ;
case Days.Sunday: d = " Today is Sunday. " ; break ;
}
return d;
}

}

public enum Days
{
///

/// this is sunday
///

Sunday = 7 ,
///

/// this is monday
///

Monday = 1 ,
///

/// this is tuesday
///

Tuesday = 2 ,
///

/// this is wednesday
///

Wednesday = 3 ,
///

/// this is thursday
///

Thursday = 4 ,
///

/// this is friday
///

Friday = 5 ,
///

/// this is saturday
///

Saturday = 6
};

 

很明显，"Today is Saturday." 当然是输出结果，可问题来了，这只是一个枚举，7条枚举值记录，假如，我要改成：hi ,cora ! this is saturday. 然后其他另外6条都不一样的，假设我们有100个或者更多这样的枚举值（只是里面的值）要更改，业务层方法GetDays这样的方法岂不是大改？（当然这只是假设，如果真实的话，或许会有更灵活的方式去处理）

晕了，小菜的又开始说BT了...

然后，我把程序稍稍改了一下，加了一个公共的类RemarkAttribute的类，然后加了一个remark的属性:

 

代码

public class RemarkAttribute : Attribute
{
private string _remark;
public RemarkAttribute( string _remark)
{
this ._remark = _remark;
}
public string Remark
{
get { return _remark; }
set { _remark = value; }
}

public static string GetEnumRemark(System.Enum _enum)
{

Type type = _enum.GetType();
FieldInfo fd = type.GetField(_enum.ToString());
if (fd == null ) return string .Empty;
object [] attrs = fd.GetCustomAttributes( typeof (RemarkAttribute), false );
string name = string .Empty;
foreach (RemarkAttribute attr in attrs)
{
name = attr.Remark;
}
return name;
}
}

 

然后把GetDays方法去掉，并且枚举加上一个属性并且加上一个属性值：

 

代码

class Program
{
static void Main( string [] args)
{

Console.Write(RemarkAttribute.GetEnumRemark(Days.Wednesday));
Console.Read();
}

}

public enum Days
{
///

/// this is sunday
///

[Remark( " this is sunday " )]
Sunday = 7 ,
///

/// this is monday
///

[Remark( " this is monday " )]
Monday = 1 ,
///

/// this is tuesday
///

[Remark( " this is tuesday " )]
Tuesday = 2 ,
///

/// this is wednesday
///

///
[Remark( " this is wednesday " )]
Wednesday = 3 ,
///

/// this is thursday
///

[Remark( " this is thursday " )]
Thursday = 4 ,
///

/// this is friday
///

[Remark( " this is friday " )]
Friday = 5 ,
///

/// this is saturday
///

[Remark( " this is saturday " )]
Saturday = 6
};

  

好了，原来的业务处理方法GetDays可以省掉了，假设（偶好象比较喜欢假设），假设我们有100个或者更多个这样的枚举值要更改，那么我们只要把Remark的属性值改一下就可以了，业务层完全不用动（当然，连整个枚举都要更改的话，我就没办法喽）。

比较简单吧？个人而言还是比较喜欢简单而又不失经典的编码方式，或者园子里的朋友有更好的方式，不防提出来分享一下吧。

 

 

 

 

转载于:https://www.cnblogs.com/kakimsun/archive/2010/04/28/1723324.html