Collection<EmployeeRecord > employees = new Collection<EmployeeRecord>();这句代码为什么要有个单书名号呢？

Question

using System;
using System.Collections.ObjectModel;
namespace Examples.DesignGuidelines.Constructors
{
    // This class can get its data either by setting 
    // properties or by passing the data to its constructor.
    public class EmployeeRecord
    {
        private int employeeId;
        private int department;
        
        public EmployeeRecord()
        {
        }
        public EmployeeRecord(int id, int department)
        {
            this.employeeId = id;
            this.department = department;
        }
        public int Department
        {
            get {return department;}
            set {department = value;}
        }
        public int EmployeeId
        {
            get {return employeeId;}
            set {employeeId = value;}
        }
        public void DisplayData()
        {
            Console.WriteLine("{0} {1}", EmployeeId, Department);
        }
    }
    // This class creates Employee records by passing 
    // argumemnts to the constructor.
    public class EmployeeManagerConstructor
    {   //
        Collection<EmployeeRecord > employees = new Collection<EmployeeRecord>();        public void AddEmployee(int employeeId, int department)
        {
            EmployeeRecord record = new EmployeeRecord(employeeId, department);
            employees.Add(record);
            record.DisplayData();
        }
    }
    // This class creates Employee records by setting properties.
    public class EmployeeManagerProperties
    {
    Collection<EmployeeRecord > employees = new Collection<EmployeeRecord>();
        public void AddEmployee(int employeeId, int department)
        {
            EmployeeRecord record = new EmployeeRecord();
            record.EmployeeId = employeeId;
            record.Department = department;
            employees.Add(record);
            record.DisplayData();
        }
    }
    public class Tester
    {
    // The following method creates objects with the same state
        // using the two different approaches.
        public static void Main()
        {
            EmployeeManagerConstructor byConstructor = 
                new EmployeeManagerConstructor();
            byConstructor.AddEmployee(102, 102);            EmployeeManagerProperties byProperties = 
                new EmployeeManagerProperties();
            byProperties.AddEmployee(102, 102);
        }
    }
}
红色带代码为什么要有个书名号呀，请教大家了。

Answer 1

泛型，详情：
http://hjf1223.cnblogs.com/archive/2005/08/25/222970.aspxhttp://www.google.cn/custom?domains=cnblogs.com&q=%E6%B3%9B%E5%9E%8B&sitesearch=cnblogs.com&client=pub-4210569241504288&forid=1&ie=UTF-8&oe=UTF-8&safe=active&cof=GALT%3A%23008000%3BGL%3A1%3BDIV%3A%23336699%3BVLC%3A663399%3BAH%3Acenter%3BBGC%3AFFFFFF%3BLBGC%3AFFFFFF%3BALC%3A0000FF%3BLC%3A0000FF%3BT%3A000000%3BGFNT%3A0000FF%3BGIMP%3A0000FF%3BLH%3A50%3BLW%3A132%3BL%3Ahttp%3A%2F%2Fwww.cnblogs.com%2Fimages%2Fcnblogs_search.gif%3BS%3Ahttp%3A%2F%2Fwww.cnblogs.com%3BFORID%3A1&hl=zh-CN