*.ashx一般处理程序不能访问Session值的解决方法

<%@ WebHandler Language="C#" Class="productHandler" %> 

using System;
using System.Web;
using JBTCard.Entity.CompanyEntity;
using JBTCard.Business.CompanyBS;
using System.Collections.Generic;
using Newtonsoft.Json;
using System.Web.SessionState; 

public class productHandler : IHttpHandler, IRequiresSessionState, IReadOnlySessionState{ 

    public void ProcessRequest (HttpContext context) {
    string moduleId = context.Request.Form["moduleId"].ToString();
    string message = "";
    switch (moduleId)
    {
    case "getPTypeList":
    IList<ProductTypeIdNameEntity> list = ProductTypeBS.GetPTypeListIdName();
    message = JavaScriptConvert.SerializeObject(list);
    break;
    case "getCompanyById":
int cid = Convert.ToInt32(context.Session["cid"]);    CompanyEntity company = CompanyBS.GetCompanyEntyById();
    message = JavaScriptConvert.SerializeObject(company);
    break;
    case "insert":
    string condis = context.Request.Form["condi"].ToString();
    ProductEntity model = (ProductEntity)JavaScriptConvert.DeserializeObject(condis, typeof(ProductEntity)); 

    bool b = ProductBS.AddProduct(model);
    if (b)
    {
    message = "{success:true}";
    }
    else
    {
    throw new Exception("商品添加失败！");
    }
break;
    }
    context.Response.ContentType = "text/javascript";
    context.Response.Write(message);
    } 

    public bool IsReusable {
        get {
            return false;
        }
    } 

} 

问了程序人生的站长，他说：

加上这句就好了：using System.Web.SessionState;