using System;
using System.Collections.Generic;
using System.Text;
using System.Web;
using System.Web.SessionState;

namespace OAFrameWork
{
  public class CSession
  {
      public static object Get(string Key)
    {
      return HttpContext.Current.Session[Key];
    }


  public static string GetString(string Key)
    {
      object obj = HttpContext.Current.Session[Key];
      if (obj == null) return "";
      else return obj.ToString();
    }


    public static object Get(string Key,object DefaultValue)
    {
      if (HttpContext.Current.Session[Key] == null)

        return DefaultValue;
      else
        return HttpContext.Current.Session[Key];

    }


    public static object Get(string Key, object DefaultValue,Boolean CanAdd)
    {
      if (HttpContext.Current.Session[Key] == null)
      {
        if(CanAdd==true)
          HttpContext.Current.Session.Add(Key, DefaultValue);

        return DefaultValue;
      }
      else
        return HttpContext.Current.Session[Key];

    }


    public static Boolean Set(string Key,object Value)
    {
      try
      {
        if (Value == null && HttpContext.Current.Session[Key] != null)
        {
          HttpContext.Current.Session.Remove(Key);
        }
        else if (HttpContext.Current.Session[Key] == null)
          {
            HttpContext.Current.Session.Add(Key, Value);
          }
          else
          {
            HttpContext.Current.Session[Key] = Value;
          }

        return true;
      }
      catch (Exception ex)
      {
        CMsgBox.Show(ex.Message); 
        return false;
      }

    }
 

      
    
  }
}

Session.Abandon();//清除全部Session
//清除某个Session
Session["UserName"] = null;
Session.Remove("UserName");