设计模式-观察者模式
观察模式：定义对象间的一种一对多的依赖关系,当一个对象的状态发生改变时, 所有依赖于它的对象都得到通知并被自动更新;
以下的列子含义：当车站要求指定的列车发车，所有在站内的列表均得到发车通知！
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using
System;
using
System.Collections.Generic;
using
System.Linq;
using
System.Text;
namespace
PatternProject
{
public
interface
ITrain
{
string
From
{
get
;
set
; }
string
To
{
get
;
set
; }
DateTime StartingDateTime
{
get
;
set
; }
void
Start(ITrain train);
}
public
interface
IStation
{
void
AddTrain(ITrain train);
void
CancelTrain(ITrain train);
void
StartNotify(ITrain train);
}
public
class
Station : IStation
{
List<ITrain> _trainList =
new
List<ITrain>();
public
void
AddTrain(ITrain train)
{
_trainList.Add(train);
}
public
void
CancelTrain(ITrain train)
{
_trainList.Remove(train);
}
public
void
StartNotify(ITrain train)
{
foreach
(ITrain t
in
_trainList)
{
t.Start(train);
}
}
}
public
class
Train : ITrain
{
public
string
From
{
get
;
set
; }
public
string
To
{
get
;
set
; }
public
DateTime StartingDateTime
{
get
;
set
; }
public
Train(
string
from
,
string
to, DateTime startingDateTime)
{
this
.From =
from
;
this
.To = to;
this
.StartingDateTime = startingDateTime;
}
public
bool
IsCurrent(ITrain train)
{
if
(train.From ==
this
.From && train.To ==
this
.To && train.StartingDateTime ==
this
.StartingDateTime)
{
return
true
;
}
else
{
return
false
;
}
}
public
void
Start(ITrain train)
{
Console.WriteLine(
"{0}开往{1}列车收到通知："
,
this
.From,
this
.To);
if
(IsCurrent(train))
{
Console.WriteLine(
"从{0}开往{1}的列车,于{2}开车，敬请注意！"
,
this
.From,
this
.To,
this
.StartingDateTime);
}
else
{
Console.WriteLine(
"还未到开车时间，敬请稍候！"
);
}
}
}
}<br><br>
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using
System;
using
System.Collections.Generic;
using
System.Linq;
using
System.Text;
namespace
PatternProject
{
class
Program
{
static
void
Main(
string
[] args)
{
Station station =
new
Station();
station.AddTrain(
new
Train(
"北京"
,
"上海"
,
new
DateTime(2014, 5, 1)));
station.AddTrain(
new
Train(
"北京"
,
"武汉"
,
new
DateTime(2014, 3, 1)));
station.AddTrain(
new
Train(
"武汉"
,
"上海"
,
new
DateTime(2014, 2, 1)));
station.AddTrain(
new
Train(
"上海"
,
"南京"
,
new
DateTime(2014, 8, 1)));
Train t =
new
Train(
"北京"
,
"武汉"
,
new
DateTime(2014, 3, 1));
station.StartNotify(t);
Console.ReadKey();
}
}
}
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本文转自 梦在旅途 博客园博客，原文链接： http://www.cnblogs.com/zuowj/p/3504852.html ，如需转载请自行联系原作者