改变已存在的cookie的cookie值 [英] Change a cookie value of a cookie that already exists

问题描述

我有一个名为SurveyCookie的cookie。创建像这样：

I have a cookie called SurveyCookie. Created like so:

var cookie = new HttpCookie("SurveyCookie");
cookie.Values["surveyPage"] = "1";
cookie.Values["surveyId"] = "1";
cookie.Values["surveyTitle"] = "Definietly not an NSA Survey....";
cookie.Values["lastVisit"] = DateTime.UtcNow.ToString();
cookie.Expires = DateTime.UtcNow.AddDays(30);
Response.Cookies.Add(cookie);

伟大的工程。现在的问题是当我想要改变价值surveyPage像这样。

Which works great. Now the problem comes when I want to change the value "surveyPage" like so.

下面将创建一个新的Cookie这是不是我想要的。

The below will create a new cookie which is not what I want.

int cookieValue = Convert.ToInt32(Request.Cookies["SurveyCookie"]["surveyPage"]) + 1;
Response.Cookies["SurveyCookie"]["surveyPage"] = cookieValue.ToString();

然后我尝试这个code以下不工作的。该surveyPage仍为1时，它应该是2。

Then I tried this code below which doesn't work either. The surveyPage is still 1 when it should be 2.

Request.Cookies["SurveyCookie"]["surveyPage"] = cookieValue.ToString(); 

由于上述两个工程是什么改变饼干值surveyPage？

Since neither of the above works what does change the cookies value for surveyPage?

推荐答案

ASP .NET饼干概述：

您不能直接修改的cookie。相反，改变一个cookie
  包括创建新值的新的cookie，然后发送的
  cookie发送到浏览器来覆盖客户端上的旧版本。

You cannot directly modify a cookie. Instead, changing a cookie consists of creating a new cookie with new values and then sending the cookie to the browser to overwrite the old version on the client.

您可以试试这个：

HttpCookie cookie = Request.Cookies["SurveyCookie"];
if (cookie == null)
{
    // no cookie found, create it
    cookie = new HttpCookie("SurveyCookie");
    cookie.Values["surveyPage"] = "1";
    cookie.Values["surveyId"] = "1";
    cookie.Values["surveyTitle"] = "Definietly not an NSA Survey....";
    cookie.Values["lastVisit"] = DateTime.UtcNow.ToString();
}
else
{
    // update the cookie values
    int newSurveyPage = int.Parse(cookie.Values["surveyPage"]) + 1;
    cookie.Values["surveyPage"] = newSurveyPage.ToString();
}

// update the expiration timestamp
cookie.Expires = DateTime.UtcNow.AddDays(30);

// overwrite the cookie
Response.Cookies.Add(cookie);

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