Interacting between user controls and parent page

Hi All,
I am working on an ecommerce website. I have used two user controls(UcControlA and UcControlB) and single parent page which uses these two user controls.
UcControlA consists various categories(like category, type, price etc..) to select from and also at the same time based on selected categories I have to display products in UcControlB. Also I need to keep updating the URL with selected catagory and add that as querystring. 
I have used the event delegation method to capture the button click in UcControlA. 
I have confusion over how to perform overall logic, and how to update the url with the selected category as querystring and agian perform data fetch from database at the same time? Is there any better way that i can perform this logic effeciently.
Any guidance would be much appreciated
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