The Basic of ASP.NET Pages -- Understand The Events

中文版(點選這裡)

Understanding the occurrence of events is helpful for programming. It is a truth for programming ASP.NET pages as well.
"It is important for you to understand the page life cycle so that you can write code at the appropriate life-cycle stage for the effect you intend."
It is quoted from a web page of Microsoft which emphasizes the importance of trigged events in the life cycle of ASP.NET pages. This "ASP.NET Page Life Cycle Overview" gives you a overall concept of events in the life cycle of ASP.NET pages.
Following is quoted form the same web page. I think it might be important for beginners of ASP.NET, just like Albert.
"Pages also support automatic event wire-up, meaning that ASP.NET looks for methods with particular names and automatically runs those methods when certain events are raised. If the AutoEventWireup attribute of the @ Page directive is set to true (or if it is not defined, since by default it is true), page events are automatically bound to methods that use the naming convention of Page_event, such as Page_Load and Page_Init."
The first line of the code of the default ASP.NET page "Default.aspx" which is created automatically after starting a brand-new ASP.NET Web Site is beneath,

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

This line, starts with @Page, has the option parameter "AutoEventWireup" and it's default value is "true". As matter of fact, the value of AutoEventWireup is set to true, it's default value, if it is omitted on purpose. The execution of codes for these event handlers depend on this option (AutoEventWireup.) And furthermore, the names of these event handlers are prefixed with "Page_", such as Page_Load, Page_Init.