.Net行为型设计模式之职责链模式（Chain of Responsibility）

static void Main(string[] args)
{
    PurchaseRequest requestDao = new PurchaseRequest(8000.0, "单刀5把");
    PurchaseRequest requestHuaJi = new PurchaseRequest(10000.0, "10把方天画戟");
    PurchaseRequest requestJian = new PurchaseRequest(80000.0, "5把金丝龙鳞闪电劈");

    Approver manager = new Manager("黄飞鸿");
    Approver financial = new FinancialManager("黄麒英");
    Approver ceo = new CEO("十三姨");

    // 设置职责链
    manager.NextApprover = financial;
    financial.NextApprover = ceo;

    // 处理请求
    manager.ProcessRequest(requestDao);
    manager.ProcessRequest(requestHuaJi);
    manager.ProcessRequest(requestJian);

}
// 采购请求
public sealed class PurchaseRequest
{
    // 金额
    public double Amount { get; set; }

    // 产品名字
    public string ProductName { get; set; }

    public PurchaseRequest(double amount, string productName)
    {
        Amount = amount;
        ProductName = productName;
    }
}

//抽象审批人,Handler---相当于“抽象处理者角色”
public abstract class Approver
{
    //下一位审批人，由此形成一条链
    public Approver NextApprover { get; set; }

    //审批人的名称
    public string Name { get; set; }

    public Approver(string name)
    {
        this.Name = name;
    }

    //处理请求
    public abstract void ProcessRequest(PurchaseRequest request);
}

//部门经理----相当于“具体处理者角色” ConcreteHandler
public sealed class Manager : Approver
{
    public Manager(string name) : base(name) { }

    public override void ProcessRequest(PurchaseRequest request)
    {
        if (request.Amount <= 10000.0)
        {
            Console.WriteLine("{0} 部门经理批准了对原材料{1}的采购计划！", this.Name, request.ProductName);
        }
        else if (NextApprover != null)
        {
            NextApprover.ProcessRequest(request);
        }
    }
}

//财务经理---相当于“具体处理者角色”ConcreteHandler
public sealed class FinancialManager : Approver
{
    public FinancialManager(string name) : base(name) { }

    public override void ProcessRequest(PurchaseRequest request)
    {
        if (request.Amount > 10000.0 && request.Amount <= 50000.0)
        {
            Console.WriteLine("{0} 财务经理批准了对原材料{1}的采购计划！", this.Name, request.ProductName);
        }
        else if (NextApprover != null)
        {
            NextApprover.ProcessRequest(request);
        }
    }
}

//总裁---相当于“具体处理者角色” ConcreteHandler
public sealed class CEO : Approver
{
    public CEO(string name) : base(name) { }

    public override void ProcessRequest(PurchaseRequest request)
    {
        if (request.Amount > 50000.0 && request.Amount < 300000.0)
        {
            Console.WriteLine("{0} 总裁批准了对原材料 {1} 的采购计划！", this.Name, request.ProductName);
        }
        else
        {
            Console.WriteLine("这个采购计划的金额比较大，需要一次董事会会议讨论才能决定！");
        }
    }
}