We can parse querystring and store the key value pair in a NameValueCollection  collection.

// Dummy query string for example.
           string strQueryString = "Player=Roger Federer&Year=2012&Title=wimbledon";

           // Parse the query string variables into a NameValueCollection.
           NameValueCollection nvcQueryString = HttpUtility.ParseQueryString(strQueryString);

           // Iterate through the collection.
           StringBuilder sbFormattesText = new StringBuilder("<br />");
           foreach (string key in nvcQueryString.AllKeys)
           {
               sbFormattesText.Append(key + " : " + nvcQueryString[key] + "<br />");
           }

           // Write the result to a label.
           lblQueryString.Text = sbFormattesText.ToString();

This is helpful when we have lot of querystring values.

http://msdn.microsoft.com/en-us/library/system.collections.specialized.namevaluecollection.aspx

http://msdn.microsoft.com/en-us/library/ms150046.aspx