Serialize, deserialize object from cookie in MVC application C#

Question

I need to store an object list in a cookie. I know that I must serialize to store my list in cookie.

I tried to use JsonConvert for serialize and deserialize Object.

This line of code works ok.

Response.Cookies.Add(new HttpCookie("ShoppingCart", JsonConvert.SerializeObject(list)));

but when I try to get the cookie value

var shoppingList = HttpContext.Request.Cookies.Get("ShoppingCart");

I get the following exception:

An exception of type 'System.Web.HttpRequestValidationException' occurred in System.Web.dll but was not handled in user code

Can you please advise what I do wrong here. Thanks! Additional information: A potentially dangerous Request.Cookies value was detected from the client (

Answer 1

The default settings in several versions of MVC block requests with HTML or XML code in the POST/GET/COOKIE.

Usually people advice to change the validation settings, but since this is only about the content of a cookie, you are probably better off encoding the information: See this duplicate question