Best practices using ADO in web forms

Experts,

newbie question.

I am pulling data from a database and populating some text boxes and combo boxes. The users can edit/delete any of these fields. They can enter new data in a control that may have not contained data to begin with.  The data is populated on the Load event. The user can do what they want and then click a "save" button.

What is a good practice to accomplish this?  If the data adapter/data set are created in the Load, then they aren't available in the button_click, correct? Do you create "global" adapters/data sets?
Or
Would you populate the controls using a data reader and then use a command to update the database from the button click?

Any guidance is appreciated.

Thanks in advance.