.NET读写cookie方法

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。

代码

   
     

    
      
    
      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

代码

   
     

    
      
    
      
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。

代码

   
     

    
      HttpCookie cookie 
    
      =
    
       
    
      new
    
       HttpCookie(
    
      "
    
      userinfo1
    
      "
    
      );
cookie.Expires
    
      =
    
      DateTime.Now.AddDays(
    
      -
    
      30
    
      ); 
Response.Cookies.Add(cookie);


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
    
       }