I'm sure there is a more ASP.NET style solution that involves reworking the connection object and moving the data pull into it's own subroutine that can be called from both the Page_load and button click event.
Honestly though, even when I was coding ASP.NET, I went out of my way to minimize the use of it's event cycle. It's just adding a layer of obscurement to the web event cycle and exists only to try and make ASP.NET and windows forms have a similar event loop. Which doesn't archive anything, good form coding and good web coding still remain vastly different, because the bottlenecks are in different places and the platform fundamentally different.
Jay