Change a cookie value of a cookie that already exists

Question

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); 

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

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(); 

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();  

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

Answer 1

From ASP.NET Cookies Overview:

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.

You can try this:

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);