IDictionary单例的写法 ，放入缓存中,vs2008,Linq应用

  

using System.Collections.Generic;
using System.Linq;

using EPMS.Domain;
using EPMS.IDao;
using EPMS.ISrv;

namespace EPMS.Srv
{
 public class ProjectRepo : IProjectRepo
 {
  protected IList<ProjectV2> _list;

        protected IProjectV2Dao _projectDao;

        /// <summary>
        /// 项目的id字典
        /// </summary>
  protected IDictionary<int, ProjectV2> _dictById;
        /// <summary>
        /// 项目Number字典
        /// </summary>
  protected IDictionary<string, ProjectV2> _dictByNumber; 

  public ProjectRepo(IProjectV2Dao projectDao)
  {
   _projectDao = projectDao;

   Reload();
  }

        /// <summary>
        /// 重新把项目信息载入字典
        /// </summary>
  public void Reload()
  {
   _list = _projectDao.SelectAll();

   IDictionary<int, ProjectV2> dictById = new Dictionary<int, ProjectV2>();
   foreach (ProjectV2 project in _list)
    dictById.Add(project.Id, project);
   _dictById = dictById;

   IDictionary<string, ProjectV2> dictByNumber = new Dictionary<string, ProjectV2>();
   foreach (ProjectV2 project in _list)
    dictByNumber.Add(project.Number, project);
   _dictByNumber = dictByNumber;
  }

  public IList<ProjectV2> GetAll()
  {
   return _list.Select(s => s.Clone()).ToList();
  }

  public ProjectV2 GetById(int id)
  {
   if (_dictById.ContainsKey(id))
    return _dictById[id].Clone();
   return null;
  }

  public ProjectV2 GetByNumber(string number)
  {
   if (_dictByNumber.ContainsKey(number))
    return _dictByNumber[number].Clone();
   return null;
  }
 }
}