How to Create Event Handler In Sharepoint ?

1. Open Visual Studio 2010.
2. On the File menu -> New and then click on Project.
3. In project type, select Event Receiver.
4. Enter Name of Event Receiver , click on Ok button.
5. Now you get Sharepoint Customization Wizard, Choose Deploy as a Sandboxed solution, click on Next.
6. In Choose Event Receiver Settings window, Select List Item Events from What type of event receiver do you want? dropdown.
7. In What item should be the event source ? dropdown, choose type of List on which you want Event Receiver.
8. Next Choose event on which you want to write code and click on finish
9. Event Receiver file is created and method for selected event is appeared.
10. Press F5 for deploy this solution.