Inside the OnItemCreated event (of the repeater), I get the ID of the textbox that I want to bind to the ControlParameter. I realized that using the ID alone was not working. I get a message saying something like "can't find txtBoxName in ControlParameter". I read somewhere that if I view the page source of the browser, then use the value in the Name attribute of the textbox (for the controlId property of the controlParameter), it works. But I also noticed that when I use a textbox outside the repeater, I could just use the ID of the textbox (without having to use page source to get the name, which is different from the ID in the aspx page, of the textbox). Can anyone explain the reasoning behind this?