put/use asp and aspx in one web application

[slatefast]

I have an exsiting C# class .cs) and want get a return string from it. my code is asp. So from one asp page, user clicks on a link to direct to an aspx file which will call this C# class and its method to get a string (this is what I am going to keep and use in asp file). Then I save the returned string to session variable, redirect back to original asp page and read that session variable.

so it could be like...

x.asp --> y.aspx (call method in cs, get return string and save it to session --> redirect back to (server.transfer) x.asp -->x.asp read session variable and dispaly it)

is this approach featheable? how to do it? can you provide me some sample code?

thanks in advance