- occurs when each row (including header, footer, pager) is created. This happens when the control is data bound as well as when it is reconstructed from viewstate on postback.
- Occurs, as the name suggests, when each item is data bound. Again, this happens for data rows as well as header, footer and pager.
- Occurs on a postback triggered by a control meeting the requirements of a delete command for a data item row. This is usually a button with the CommandName of "Delete".
- Occurs on a postback triggered by a button in a gridview.
As I suggested before, take a look at the MSDN docs for the gridview events:
The best way to understand any control events is to create a test page with the control, set up event handlers for all the events you want to investigate and either run in the debugger or have each handler generate some output so you can see how it works.