问题
I have a Master page and a webpage that uses the Master page.
In both I have a Page_Load event handler.
In which order are the Page_Load handlers called? Content first then Master or Master first then content?
回答1:
The content page load event will fire before the master page load event.
See here for full order (MSDN: Events in ASP.NET Master and Content Pages)
Copying incase link goes dead:
The following is the sequence in which events occur when a master page is merged with a content page:
1 - Content page PreInit event.
2 - Master page controls Init event.
3 - Content controls Init event.
4 - Master page Init event.
5 - Content page Init event.
6 - Content page Load event.
7 - Master page Load event.
8 - Master page controls Load event.
9 - Content page controls Load event.
10 - Content page PreRender event.
11 - Master page PreRender event.
12 - Master page controls PreRender event.
13 - Content page controls PreRender event.
14 - Master page controls Unload event.
15 - Content page controls Unload event.
16 - Master page Unload event.
17 - Content page Unload event.
回答2:
As far as MasterPage is indeed a user control all rules applied to it as for user controls:
回答3:
Master pages run Page_Load() from the deepest level of nesting outwards. So your nested webpage will first run the page_load event.
来源：https://stackoverflow.com/questions/4470196/which-event-called-first-master-page-page-load-or-content-page-page-load