Modelling User Interface and Datasets


I am very new to UML and I was wondering if some one can help me with a question, ok, if we create a class for our User Interface(UI) and say we have a class Customer and Customer is associated to class Order, one to many. And we have a datagrid of Orders for a specific customer in our UI. The thing is the datagrid needs a dataset to be populated and where does it get the dataset of customer orders?..from the Customer Class/ Order Class/ Interface Class/ A Common Static Class(for all datasets?). The thing is, if i model an object do I have to consider how it will populate lists/grids/etc when modelling, and if the grid changes columns etc how do I model with the least adaptation of code?

Thanks in advance,