query string analysis ?/

Well, the Wikipedia article on query strings is as good as anything for understanding them:

http://en.wikipedia.org/wiki/Query_string

In general, you can extract the field-value pairs from the query string with code such as this:

using System;
using System.Web;
using System.Collections.Specialized;

class Test
{
   static void Main()
   {
     string query = "sdsffeojsjdb%slcxa&1||b&2||sum1&2"; // or whatever
     NameValueCollection nvc = HttpUtility.ParseQueryString(query);
     foreach (string field in nvc.AllKeys )
     {
        Console.WriteLine( " {0} -> {1}", field, nvc[field] );
     }
     Console.ReadKey();
   }
}

However, it looks to me like the query string you've posted (i.e. the part after the '?' sign) is not well-formed as there are no '=' signs in it.