Cookie是一段文本信息,在客户端存储 Cookie 是 ASP.NET 的会话状态将请求与会话关联的方法之一。Cookie 也可以直接用于在请求之间保持数据，但数据随后将存储在客户端并随每个请求一起发送到服务器。浏览器对 Cookie 的大小有限制，因此，只有不超过 4096 字节才能保证被接受。
编写Cookie
//方式1:
Response.Cookies["username"].value="mike";
Response.Cookies["username"].Expires=DateTime.MaxValue;
//方式2:
HttpCookie acookie = new HttpCookie("last");
acookie.Value="a";
acookie..Expires=DateTime.MaxValue;
Response.Cookies.Add(acookie);
//多值Cookie的写法
//方式1:
Response.Cookies["userinfo1"]["name"].value="mike";
Response.Cookies["userinfo1"]["last"].value="a";
Response.Cookies["userinfo1"].Expires=DateTime.MaxValue;
//方式2:
HttpCookie cookie = new HttpCookie("userinfo1");
cookie.Values["name"]="mike";
cookie.Values["last"]="a";
cookie.Expires=DateTime.MaxValue;
//cookie.Expires = System.DateTime.Now.AddDays(1);//设置过期时间 1天
Response.Cookies.Add(cookie);
读取Cookie
Internet Explorer 将站点的 Cookie 保存在文件名格式为 <user>@<domain>.txt 的文件中，其中 <user> 是您的帐户名。
注意:在获取Cookie的值之前，应该确保该 Cookie 确实存在。否则，您将得到一个异常
If (Request.Cookies["userName"]!=null)
{
string str = Request.Cookies("userName").Value;
}
//多值Cookie的读取
If ( Request.Cookies["userInfo1"]!=null )
{
string name=Request.Cookies["userInfo1"]["name"];
string last=Request.Cookies["userInfo1"]["last"];
}
//读取 Cookie 集合
for(int i = 0 ;i<Request.Cookies.Count ;i++)
{
HttpCookie cookies = Request.Cookies;
Response.Write("name="+cookies.Mame+"<br/>");
if (cookies.HasKeys )//是否有子键
{
System.Collections.Specialized.NameValueCollection NameColl
= aCookie.Values ;
for(int j=0;j<NameColl.Count;j++)
{
Response.Write("子键名="+ NameColl.AllKey[j] +"<br/>");
Response.Write("子键值="+ NameColl[j] +"<br/>");
}
}
else
{
Response.Write("value="+cookies.Value+"<br/>");
}
}
运行此代码时，可看到一个名为“ASP.NET_SessionId”的Cookie，ASP.NET用这个 Cookie 来保存您的会话的唯一标识符。
修改 Cookie
修改的方法与创建方法相同
删除 Cookie
将其有效期设置为过去的某个日期。当浏览器检查 Cookie 的有效期时，就会删除这个已过期的 Cookie。
HttpCookie cookie = new HttpCookie("userinfo1");
cookie.Expires=DateTime.Now.AddDays(-30);
Response.Cookies.Add(cookie);
============================实例。
//----------写入Cookie
HttpCookie cookie = new HttpCookie("userinfo1");
cookie.Expires = System.DateTime.Now.AddMinutes(2);//设置过期时间
for (int i = 0; i < 20; i++)
{
cookie.Values["Val" +i.ToString()] = i.ToString();
Response.Cookies.Add(cookie);
}
//读取 Cookie 集合
for (int i = 0; i < Request.Cookies.Count; i++)
{
if (Request.Cookies.AllKeys[i] == "userinfo1")
{
HttpCookie cookies = Request.Cookies["userInfo1"];
Response.Write("name=" + cookies.Name + "<br/>");
//Response.Write("name=" + cookies.Value + "<br/>");
if (cookies.HasKeys)//是否有子键
{
System.Collections.Specialized.NameValueCollection NameColl = cookies.Values;
for (int j = 0; j < NameColl.Count; j++)
{
Response.Write("子键名=" + NameColl.AllKeys[j] + "<br/>");
Response.Write("子键值=" + NameColl[j] + "<br/>");
}
}
else
{
Response.Write("value=" + cookies.Value + "<br/>");
}
}
}
/////********************************************************************
修改cookie
1 Response.Cookies["Info"]["user"] = "2";
2 Response.Cookies["Info"].Expires = DateTime.Now.AddDays(1); 删除cookie下的属性
1 HttpCookie acookie=Request.Cookies["Info"];
2 acookie.Values.Remove("userid");
3 acookie.Expires = DateTime.Now.AddDays(1);
4 Response.Cookies.Add(acookie); 删除所有cookie，就是设置过期时间为现在就行了
1 int limit=Request.Cookies.Count - 1;
2 for(int i=0;i<limit;i++)
3 {
4 acookie = Request.Cookies(i)
5 acookie.Expires = DateTime.Now.AddDays(-1)
6 Response.Cookies.Add(acookie)
7 } 这下不用到处找了
