My buddy Spook was lamenting the other day about the unintuitive behavior of the ASP.Net Cookies collection. You can read the fully bits here before continuing.

I decided that methinks this is a case for some extension methods! If you are someone that wants to tweak this behavior to support the pattern outlined by Spook then feel free to snag the code and use on your own.

 

// http://www.zimms.com
// Copyright (c) 2009
// by James Zimmerman
//
// http://blogs.msdn.com/schlepticons/archive/2009/08/07/extension-methods-to-reduce-aspnet-cookies-collection-bugs.aspx
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in the
// Software without restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
// Software, and to permit persons to whom the Software is furnished to do so, subject
// to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies
// or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.public static class HttpCookieCollectionExtensions
{
    public static void SafeAdd(this HttpCookieCollection cookies, HttpCookie cookie)
    {
        SafeAdd(cookies, cookie, false);
    }

    public static void SafeAdd(this HttpCookieCollection cookies, HttpCookie cookie, Boolean allowDuplicates)
    {
        HttpCookieCollection requestCookies = HttpContext.Current.Request.Cookies;
        if (requestCookies == null) return;
        var items = requestCookies.AllKeys.Where(key => key == cookie.Name).ToList();
        if (!allowDuplicates) items.ForEach(requestCookies.Remove);
        cookies.Add(cookie);
    }
}