cookie得不到值？该怎么处理

cookie得不到值？
像这样的代码：
case   "itshop ":
csover.reg.bin.user_Itsun   Ituser=new   user_Itsun();
Ituser.username=this.txtName.Text.Trim();
Ituser.Password=calyx.reg.bin.Function_all.Encrypts(this.txtPas.Text.Trim(),1);
if(Ituser.Itsun_Login())
{
try
{
HttpCookie   MyCookie   =   new   HttpCookie( "itshop ");
MyCookie.Value   =   "admin ";
Response.Cookies.Add(MyCookie);

Response.Redirect   ( "middle.aspx ");
}
catch(Exception   ex)
{
this.msg.Text= "得到错误信息！ "   +   ex.Message;
}
}
else
{
this.msg.Text= "对不起，请输入正确的用户名与密码！ ";
}
break;

执行这段代码后，为啥在asp中运用   response.write   Request.Cookies( "itshop ")打印出来是空白的呢？

------解决方案--------------------------------------------------------
MyCookie.Value = "admin ";
后面加

vb.net

MyCookie.Expires=system.DateTime.Now.AddDays(1)