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
{
///
<summary>
///
this is sunday
///
</summary>
Sunday
=
7
,
///
<summary>
///
this is monday
///
</summary>
Monday
=
1
,
///
<summary>
///
this is tuesday
///
</summary>
Tuesday
=
2
,
///
<summary>
///
this is wednesday
///
</summary>
Wednesday
=
3
,
///
<summary>
///
this is thursday
///
</summary>
Thursday
=
4
,
///
<summary>
///
this is friday
///
</summary>
Friday
=
5
,
///
<summary>
///
this is saturday
///
</summary>
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
{
///
<summary>
///
this is sunday
///
</summary>
[Remark(
"
this is sunday
"
)]
Sunday
=
7
,
///
<summary>
///
this is monday
///
</summary>
[Remark(
"
this is monday
"
)]
Monday
=
1
,
///
<summary>
///
this is tuesday
///
</summary>
[Remark(
"
this is tuesday
"
)]
Tuesday
=
2
,
///
<summary>
///
this is wednesday
///
</summary>
///
[Remark(
"
this is wednesday
"
)]
Wednesday
=
3
,
///
<summary>
///
this is thursday
///
</summary>
[Remark(
"
this is thursday
"
)]
Thursday
=
4
,
///
<summary>
///
this is friday
///
</summary>
[Remark(
"
this is friday
"
)]
Friday
=
5
,
///
<summary>
///
this is saturday
///
</summary>
[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。