I was writing dynamic form variables to the page and i needed to retrieve their values when updated. When i tried to access the variables with request.params[] collection i noticed that the keys were what id i had given them with a string appended to the start. I wrote this function to easiliy access the variables:-

public static string PostVal(string key)
    {
        string retval = "";
        foreach (string s in HttpContext.Current.Request.Form.AllKeys)
        {
            string[] sr = s.Split('$');
            if (sr[sr.Length - 1] == key)
            {
                retval = HttpContext.Current.Request.Form[s];
            }
        }
        return retval;
    }