Loading user controls dynamically

How to load a user control dynamically in a page?
I have a page that contains radioButtons. Each click on a radio button loads a user control (.ascx) in the page.
What I am doing is loading all controls at the same time, but set their visibility to false. When a user clicks a radiobutton I set the visibility of the specific user control to true.
As a result I am loading all the user controls on each postback.
Is there any other possible way of doing this?

How can I re-instantiate dynamic ASP.NET user controls without using a database?

I’m currently working with a part of my application that uses Dynamic Web User Controls and I’m having a bit of trouble figuring out the best way to re-instantiate the controls on postback by using ViewState or some other method that doesn’t require me to query a database on each postback.