问题
What is difference between page_load and onLoad functions in ASP.NET codebehind?
回答1:
Load is the event and OnLoad is a method that raises that event when called
it's just base class implementation that does it of course, and therefore
needs to be called from deriving classes so that events work)
回答2:
You should probably read the Page Lifecycle Overview for more info.
This little bit should help clear up the difference:
Note that when an event handler is created using the Page_event syntax, the base implementation is implicitly called and therefore you do not need to call it in your method. For example, the base page class's OnLoad method is always called, whether you create a Page_Load method or not. However, if you override the page OnLoad method with the override keyword (Overrides in Visual Basic), you must explicitly call the base method. For example, if you override the OnLoad method on the page, you must call base.Load (MyBase.Load in Visual Basic) in order for the base implementation to be run.
and
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, page events are automatically bound to methods that use the naming convention of Page_event, such as Page_Load and Page_Init.
The OnLoad is part of the page and is always called. You don't need to have a Page_Load method which is just optional extension of the event.
回答3:
They handle the same event but Page_Load() works only when AutoEventWireup="true".
回答4:
OnLoad fires the Load event, which Page_Load is a default event handler.
来源：https://stackoverflow.com/questions/3464898/difference-between-page-load-and-onload