How to dynamically add and remove Controls in ASP.Net

I have seen manyapplication where there is a logic like
Txtname Txtlast name
<Button: Add More rows>on click on of button another row added
Txtname Txtlast name
<Button: Add More rows>on click on of button another row added
<Button: Save>
on click on save all therows filled data is inserted in to database rows.



how to achive this logic in ASP.NET