访问者模式

/*
 * User: Administrator
 * Date: 2007-7-3 Time: 10:26
 */
using System;
using System.Collections;

namespace TreeViewVisitable
{
    public interface IVisitable{
        void Accept (Visitor v);
    }

    public abstract class Visitor{
        public Visitor(){}
        public abstract void VisitCompany(Company c);
        public abstract void VisitDepartment(Department c);
        public abstract void VisitEmployee(Employee e);
    }

    public class Company:IVisitable{
        private string name;
        private ArrayList myDepartments;

        public Company(){
            myDepartments=new ArrayList();
        }

        public ArrayList Departments{
            get{return myDepartments;}
        }

        public string CompanyName{
            get{return name;}
            set{name=value;}
        }

        #region IVisitalbe 成员
        public void Accept(Visitor v){
            v.VisitCompany(this);
        }
        #endregion
    }
    public class Department:IVisitable{
        private string name;
        private ArrayList myEmployees;
        private Employee dLeader;

        public Department(){
            myEmployees=new ArrayList();
        }
        public string DepartName{
            get{return name;}
            set{name=value;}
        }

        public Employee Leader
        {
            get{return dLeader;}
            set{dLeader=value;}
        }

        public ArrayList Employee
        {
            get{return myEmployees;}
            set{myEmployees=value;}
        }

        #region IVisitable 成员
        public void Accept(Visitor v)
        {
            v.VisitDepartment(this);
        }
        #endregion
    }

    public class Employee:IVisitable
    {
        public Employee(){}
        private string name;

        public string Name{
            get{return name;}
            set{name=value;}
        }
        #region IVisitable 成员
        public void Accept(Visitor v){
            v.VisitEmployee(this);
        }
        #endregion


    }

    public class NameVisitor:Visitor
    {
        public NameVisitor(){}
        private string name;
        public string Name{get{return name;}}
        public override void VisitCompany(Company c)
        {
            name=c.CompanyName;
        }
        public override void VisitDepartment(Department c)
        {
            name=c.DepartName;
            //base.VisitDepartment(c);
        }
        public override void VisitEmployee(Employee e)
        {
            name=e.Name;
            //base.VisitEmployee(e);
        }
    }

    public class DetailVisitor:Visitor{
        public DetailVisitor(){}

        private string detail;
        public string Detail
        {
            get{return detail;}
        }

        public override void VisitCompany(Company c)
        {
            detail=string.Empty;
            detail+=c.CompanyName+" ";
            detail+="共有"+c.Departments.Count.ToString()+"个部门";
            //base.VisitCompany(c);
        }

        public override void VisitDepartment(Department c)
        {
            detail=string.Empty;
            detail+=c.DepartName+" ";
            detail+="共有"+c.Employee.Count+"个员工";
            detail+="领导是"+c.Leader.Name;
            //base.VisitDepartment(c);
        }

        public override void VisitEmployee(Employee e)
        {
            detail=string.Empty;
            detail+="员工的姓名是"+e.Name;
            //base.VisitEmployee(e);
        }


    }

}


private ArrayList dp=new ArrayList();
private NameVisitor nv=new NameVisitor();
private DetailVisitor dv=new DetailVisitor();
void Button1Click(object sender, EventArgs e)
{
try
{


    Company  c=new Company();

    c.CompanyName="测试公司";

    Department d=new Department();
    d.DepartName="软件部";
    Employee e1=new Employee();
    e1.Name="佳艺";

    d.Leader=e1;
    d.Employee.Add(e);

    Employee e2=new Employee();
    e2.Name="e2";
    d.Employee.Add(e2);

    Employee e3=new Employee();
    e3.Name="e3";
    d.Employee.Add(e3);

    c.Departments.Add(d);


    dp.Add(c);
    ShowCompanies();

    }
catch(Exception ex)
{
    MessageBox.Show(ex.ToString());
}
}

private void ShowCompanies()
{
    foreach(Company c in dp)
    {
        c.Accept(nv);
        string name=nv.Name;
        TreeNode n=treeView1.Nodes.Add(name);
        n.Tag=c;
        ShowDepartments(c,n);
    }
}

private void ShowDepartments(Company c ,TreeNode on)
{
    foreach(Department d in c.Departments){
        d.Accept(nv);
        string name=nv.Name;
        TreeNode n=on.Nodes.Add(name);
        n.Tag=d;
        ShowEmployee(d,n);
    }
}

private void ShowEmployee(Department d,TreeNode n)
{
    foreach(Employee e in d.Employee){
        d.Accept(nv);
        string name=nv.Name;
        TreeNode on=n.Nodes.Add(name);
        on.Tag=e;
    }
}


void TreeView1AfterSelect(object sender, TreeViewEventArgs e)
{
    IVisitable cde=(IVisitable)e.Node.Tag;
    cde.Accept(dv);
    MessageBox.Show(dv.Detail);
}