当很多对象都有机会处理请求，从而避免请求的发送者和接受者之间的耦合，将这个对象连成一条链，并沿着链处理请求，直到有一个对象处理它为止。
图示：
请假加薪的实例：
//申请
class Request {
//申请类别
private string requestType;
public string RequestType {
get { return requestType; }
set { requestType = value; }
}
//申请内容
private string requestContent;
public string RequestContent {
get { return requestContent; }
set { requestContent = value; }
}
//申请数量
private int number;
public int Number {
get { return number; }
set { number = value; }
}
}
//管理者
abstract class Manager {
protected string name;
protected Manager superior; //管理者的上级
public Manager(string name) {
this.name = name;
}
public void setsuperior(Manager superior) {
this.superior = superior;
}
//申请请求
abstract public void RequestApplications(Request request);
}
//经理
class CommonManager : Manager {
public CommonManager(string name) : base(name) { }
public override void RequestApplications(Request request)
{
//throw new NotImplementedException();
if (request.RequestType == "请假" && request.Number <= 2)
{
Console.WriteLine("{0}:{1}数量{2}被批准", name, request.RequestContent, request.Number);
}
else {
if (superior != null) {
superior.RequestApplications(request );
}
}
}
}
//总监同样继承管理者类
class Majordomo : Manager {
public Majordomo(string name):base (name)
{
}
public override void RequestApplications(Request request)
{
//throw new NotImplementedException();\
if (request.RequestType == "请假" && request.Number <= 5)
{
Console.WriteLine("{0}:{1}数量{2}被批准", name, request.RequestContent, request.Number);
}
else {
if (superior != null)
{
superior.RequestApplications(request);
}
}
}
}
//总经理
class GeneralManager : Manager {
public GeneralManager(string name) : base(name) { }
public override void RequestApplications(Request request)
{
//throw new NotImplementedException();
if (request.RequestType == "请假")
{
Console.WriteLine("{0}:{1}数量{2}被批准", name, request.RequestContent, request.Number);
}
else if (request.RequestType == "加薪" && request.Number <= 500)
{
Console.WriteLine("{0}:{1}数量{2}被批准", name, request.RequestContent, request.Number);
}
else {
Console.WriteLine("{0}:{1}数量{2} 再说吧", name, request.RequestContent, request.Number);
}
}
}
class Program
{
static void Main(string[] args)
{
CommonManager jinli = new CommonManager("金立");
Majordomo zongjian = new Majordomo("总监");
GeneralManager zhongjingli = new GeneralManager("总经理");
jinli.setsuperior(zongjian );
zongjian.setsuperior(zhongjingli );
Request request = new Request();
request.RequestType = "请假";
request.RequestContent = "小菜请假";
request.Number = 4;
jinli.RequestApplications(request );
Request request2 = new Request();
request2.RequestType = "请假";
request2.RequestContent="小菜请假";
request2.Number = 4;
jinli.RequestApplications(request2 );
Request request3 = new Request();
request3.RequestType = "加薪";
request3.RequestContent = "小菜请求加薪";
jinli.RequestApplications(request3 );
Request request4 = new Request();
request4.RequestType = "加薪";
request4.RequestContent = "小菜请求加薪";
request4.Number = 1000;
jinli.RequestApplications(request4);
Console.Read();
}
}
运行结果：
