To create an event handler with the default name, double-click the text box next to the event name in the Properties window. To create an event handler with a custom name, type the name of your choice into the text box and press enter. The event handler is created and the code-behind file is opened in the code editor. The event handler method has 2 parameters. The first is sender, which is a reference to the object where the handler is attached. The sender parameter is an Object type. You typically cast sender to a more precise type if you expect to check or change the state on the sender object itself. Based on your own app design, you expect a type that is safe to cast the sender to, based on where the handler is attached. The second value is event data, which generally appears in signatures as the e or args parameter.