When to use Application_Start vs Init in Global.as

问题:

I am wondering under what circumstances I should be putting application initialisation code in Application_Start() vs Init() in my Global.asax file?

The distinction between the two doesn't seem very obvious to me, other than Application_start gets called first, then Init().

• Why would I use one over the other?
• Does it really make a difference?
• What changes in the application state between the two events?

So far the only real pointer I can find is that IHttpModule only has an Init() method, so if what I'm doing may at some point be better suited to implement IHttpModule I should use the Init() method of Global.asax, if nothing else for consistency.

回答1:

From the MSDN docs:

The Application_Start and Application_End methods are special methods that do not represent HttpApplication events. ASP.NET calls them once for the lifetime of the application domain, not for each HttpApplication instance.

Init:

Called once for every instance of the HttpApplication class after all modules have been created.

UPDATE: if you need to make sure a certain code is called only once in the app. lifecycle, Application_Start is a better solution. Examples: configuring log4net?

回答2:

Yes

There are differences between them. Application_Start() event is called just one time while Init() method is called on each time when instance of the application is created.