One way to achieve this with little headache is to decrypt the query string as you currently do, then set its values to some object which can be stored in the session. Storing it in a session variable would be useful if you wanted to exclude this information (hide) from the query string - you'd essentially be passing the data around behind the scenes.
Once stored in session, you would then change your code, such that wherever you use querystring["var"]
, you will instead refer to the object that has been stored in the session.
Edit
Note, though, that this doesn't have to be relegated to a single value. This object can have multiple properties each representing a query string value:
MyQueryStringObject myQueryStringObject = new MyQueryStringObject(SomeUrl);
//MyQueryStringObject decrypts the query string and assigns the values to properties in its constructor
string abc = myQueryStringObject.abc;
string xyz = myQueryStringObject.xyz;
Now, that uses properties to represent each query string value. You may have tons of them. In that case, you can store the values into some sort of Dictionary
or a NameValueCollection
perhaps.
There are various ways to achieve this which I think is beyond topic, but, note that the key to all of this, the very essence is to simply decrypt the url on the server (during postback) and save the unencrypted data into a session variable should you want to hide it from the URL.