How to create checkboxlist using c# dynamically?

Question

I have 3 levels of selection.
In the first levelI have to disply all the industries in a check box list from the database.
The user is allowed to select any number of industries and based on those selections
I have to show the  categories which comes under each industry in seperate checkbox lists.
The user is allowed to select any number of categories and based on these selections
I have to show the subcategories of each category.
So, I don't know how to generate checkboxlist using c#?