asp.net cookie操作-添加cookie，添加键值，移除cookie，移除键值

  1 public class Cookies
  2 {
  3     /// <summary>
  4     /// 添加cookie
  5     /// </summary>
  6     /// <param name="cookieName"></param>
  7     /// <param name="value"></param>
  8     public static void Add(string cookieName, string value)
  9     {
 10         HttpCookie cookie = new HttpCookie(HttpUtility.UrlEncode(cookieName), HttpUtility.UrlEncode(value));
 11         HttpContext.Current.Response.AppendCookie(cookie);
 12     }
 13 
 14     /// <summary>
 15     /// 给指定的cookie的指定键添加值
 16     /// </summary>
 17     /// <param name="cookieName">cookie的名称</param>
 18     /// <param name="keyName">要添加的键</param>
 19     /// <param name="value">要添加的值</param>
 20     public static void Add(string cookieName, string keyName, string value)
 21     {
 22         HttpCookie cookie = HttpContext.Current.Request.Cookies[cookieName];
 23         //如果cookie=null则新建一个cookie
 24         if (cookie == null)
 25             cookie = new HttpCookie(HttpUtility.UrlEncode(cookieName));
 26         //如果该键不存在，则新建一个键值并赋值；否则直接赋值
 27         if (string.IsNullOrEmpty(cookie.Values[keyName]))
 28             cookie.Values.Add(keyName, HttpUtility.UrlEncode(value));
 29         else
 30             cookie.Values[keyName] = HttpUtility.UrlEncode(value);
 31 
 32         HttpContext.Current.Response.AppendCookie(cookie);
 33     }
 34 
 35     /// <summary>
 36     /// 读取Cookie
 37     /// </summary>
 38     /// <param name="key"></param>
 39     /// <returns></returns>
 40     public static string GetValue(string cookieName)
 41     {
 42         string value = HttpContext.Current.Request.Cookies[HttpUtility.UrlEncode(cookieName)].Value;
 43         return string.IsNullOrEmpty(value) ? string.Empty : HttpUtility.UrlDecode(value);
 44     }
 45 
 46     /// <summary>
 47     /// 读取指定Cookie里的指定键的值
 48     /// </summary>
 49     /// <param name="cookieName">cookie名称</param>
 50     /// <param name="keyName">cookie的键</param>
 51     /// <returns></returns>
 52     public static string GetValue(string cookieName, string keyName)
 53     {
 54         HttpCookie cookie = HttpContext.Current.Request.Cookies[HttpUtility.UrlEncode(cookieName)];
 55         if (cookie == null)
 56             return string.Empty;
 57         string value = cookie.Values[HttpUtility.UrlEncode(keyName)];
 58         return string.IsNullOrEmpty(value) ? string.Empty : HttpUtility.UrlDecode(value);
 59     }
 60 
 61     /// <summary>
 62     /// 获取指定cookie中所有的键
 63     /// </summary>
 64     /// <param name="cookieName"></param>
 65     /// <returns></returns>
 66     public static string[] GetValues(string cookieName)
 67     {
 68         if (HttpContext.Current.Request.Cookies[cookieName] == null)
 69             return new string[0];
 70         string[] keys = HttpContext.Current.Request.Cookies[cookieName].Values.AllKeys;
 71         for (int i = 0; i < keys.Length; i++)
 72         {
 73             keys[i] = HttpUtility.UrlDecode(keys[i]);
 74         }
 75         return keys;
 76     }
 77 
 78     /// <summary>
 79     /// 移除指定的Cookie
 80     /// </summary>
 81     /// <param name="cookieName"></param>
 82     public static void Remove(string cookieName)
 83     {
 84         HttpContext.Current.Response.Cookies.Remove(HttpUtility.UrlEncode(cookieName));
 85         HttpContext.Current.Response.Cookies[HttpUtility.UrlEncode(cookieName)].Expires = DateTime.Now.AddDays(-1);
 86     }
 87     /// <summary>
 88     /// 移除cookie中指定的键，若是最后一个键则移除这个cookie
 89     /// </summary>
 90     /// <param name="cookieName"></param>
 91     /// <param name="keyName"></param>
 92     public static void Remove(string cookieName, string keyName)
 93     {
 94         HttpCookie cookie = HttpContext.Current.Request.Cookies[cookieName];
 95         if (cookie != null)
 96         {
 97             if (cookie.Values.Count > 0)
 98             {
 99                 if (cookie.Values.Count == 1)
100                 {
101                     //若是最后一个键则移除这个cookie,否则会多出一个空值
102                     cookie.Values.Remove(HttpUtility.UrlEncode(keyName));
103                     cookie.Expires = DateTime.Now.AddDays(-1);
104                 }
105                 else
106                 {
107                     cookie.Values.Remove(HttpUtility.UrlEncode(keyName));
108                 }
109                 HttpContext.Current.Response.Cookies.Add(cookie);
110             }
111         }
112     }
113 }

首先要了解Cookie是存在客户端的。

添加cookie是向客户端添加cookie，所以要用(Response)HttpContext.Current.Response.AppendCookie(cookie);

获取cookie是获取客户端提交上来的cookie，所以要用(Request)HttpContext.Current.Request.Cookies[cookieName];

服务器端没有权限删除客户端上的文件，所以服务器端，不能删除cookie。但可以让浏览器删除，即让cookie过期。

关于cookie读取中文cookie时出现乱码：存储中文时要进行编码，读取中文时则进行解码，这样可以避免出现乱码。

cookie中存储数据的格式是以值键对的形式存储的：即 key1=value1&key2=value2;

所以

1 cookie.Values.Add(key1, value1);
2 和
3 cookie.Value=cookie.Value+"&key1=value1"
4 是等同的。但是后者在Request.Cookies[cookieName].Values.Count时则会变成1。
5 可能是加上新值之后编码不一所以count的时候变成了1