Dynamically Creating a Parameter Input Page - Best Practice?

I have a Reporting WebApp in which users select a report from a DropDownList and then clicks the "Generate" button. The reports may or may not require parameters. I'm able to determine the number and type of the parameter(s) from the Parameters collection . Based on that information I would like to generate a parameter input page.  

So my questioin is: What is a "Best Practice" for creating a parameter input page based on changing numbers and types of parameters?

Thanks
Jerry