asp.net - Get the repeater selected item on pageinit -

I also have a menu like the navigation pane (also repeater) and the placeholder in these pages.

This is my problem: Click on the menu item, I open a separate control over a click in my placeholder. When I change the selected items in my menu on my page, I load the old control and I load new controls on the menu event. How can I load a selected item of a repeater on page indicator, item link button

My Do not add a link button, but postback with HTML link and _doPostback, I can hold the value of eventargrt