How to read controls added in controls collection.

[C# Programming]

I add different controls like RadioButtons, CheckBoxes, text boxes, labels, in the controls collection of a windows form at run time to render different Question and their options to generate a Questionare. now i want to read these controls one by one to store data from selected controls(radiobuttons, checkbox). but iam failed to do so.
PLZ help me how i read these controls at run tome, in windows application.