Where to put try catch

Question

Consider this scenario: I have 3-layer app, when the user click on the button the button event handler calls a method in biz layer that do whatever with data my button even

Answer 1

UI is just for presentation. You don't catch exceptions there, because figuring out what to do with it means logic. That belongs in business or controller layers. At worst, you catch the exception and map it to an appropriate, user-friendly error message that is then sent to the presentation for display.