Understanding the Page Life Cycle can be very important as you begin to build Pages with MasterPages and UserControls.
Does the Init event fire first for the Page, the MasterPage or the UserControl?
What about the Load event?
If you make an incorrect assumption about the sequence that these events fire, then you may end up with a page that simply doesn't behave the way you had anticipated.
By running a simple test, we can see exactly when each event fires. Our test setup is composed of a Page, MasterPage, UserControl, Nested UserControl and Button control as follows:
BeginRequest - HttpModule
AuthenticateRequest - HttpModule
PostAuthenticateRequest - HttpModule
PostAuthorizeRequest - HttpModule
ResolveRequestCache - HttpModule
PostResolveRequestCache - HttpModule
PostMapRequestHandler - HttpModule
AcquireRequestState - HttpModule
PostAcquireRequestState - HttpModule
PreRequestHandlerExecute - HttpModule
PreInit - Page
Init - ChildUserControl
Init - UserControl
Init - MasterPage
Init - Page
InitComplete - Page
LoadPageStateFromPersistenceMedium - Page
ProcessPostData (first try) - Page
PreLoad - Page
Load - Page
Load - MasterPage
Load - UserControl
Load - ChildUserControl
ProcessPostData (second try) - Page
RaiseChangedEvents - Page
RaisePostBackEvent - Page
Click - Button - ChildUserControl
DataBinding - Page
DataBinding - MasterPage
DataBinding - UserControl
DataBinding - ChildUserControl
LoadComplete - Page
PreRender - Page
PreRender - MasterPage
PreRender - UserControl
PreRender - ChildUserControl
PreRenderComplete - Page
SaveViewState - Page
SavePageStateToPersistenceMedium - Page
SaveStateComplete - Page
Unload - ChildUserControl
Unload - UserControl
Unload - MasterPage
Unload - Page
PostRequestHandlerExecute - HttpModule
ReleaseRequestState - HttpModule
PostReleaseRequestState - HttpModule
UpdateRequestCache - HttpModule
PostUpdateRequestCache - HttpModule
EndRequest - HttpModule
PreSendRequestHeaders - HttpModule
PreSendRequestContent - HttpModule
Does the Init event fire first for the Page, the MasterPage or the UserControl?
What about the Load event?
If you make an incorrect assumption about the sequence that these events fire, then you may end up with a page that simply doesn't behave the way you had anticipated.
By running a simple test, we can see exactly when each event fires. Our test setup is composed of a Page, MasterPage, UserControl, Nested UserControl and Button control as follows:
- The Page is tied to the MasterPage
- The UserControl is on the Page
- The Nested UserControl is on the UserControl
- The Button is on the Nested UserControl.
- Clicking the Button calls the Page.DataBind method
BeginRequest - HttpModule
AuthenticateRequest - HttpModule
PostAuthenticateRequest - HttpModule
PostAuthorizeRequest - HttpModule
ResolveRequestCache - HttpModule
PostResolveRequestCache - HttpModule
PostMapRequestHandler - HttpModule
AcquireRequestState - HttpModule
PostAcquireRequestState - HttpModule
PreRequestHandlerExecute - HttpModule
PreInit - Page
Init - ChildUserControl
Init - UserControl
Init - MasterPage
Init - Page
InitComplete - Page
LoadPageStateFromPersistenceMedium - Page
ProcessPostData (first try) - Page
PreLoad - Page
Load - Page
Load - MasterPage
Load - UserControl
Load - ChildUserControl
ProcessPostData (second try) - Page
RaiseChangedEvents - Page
RaisePostBackEvent - Page
Click - Button - ChildUserControl
DataBinding - Page
DataBinding - MasterPage
DataBinding - UserControl
DataBinding - ChildUserControl
LoadComplete - Page
PreRender - Page
PreRender - MasterPage
PreRender - UserControl
PreRender - ChildUserControl
PreRenderComplete - Page
SaveViewState - Page
SavePageStateToPersistenceMedium - Page
SaveStateComplete - Page
Unload - ChildUserControl
Unload - UserControl
Unload - MasterPage
Unload - Page
PostRequestHandlerExecute - HttpModule
ReleaseRequestState - HttpModule
PostReleaseRequestState - HttpModule
UpdateRequestCache - HttpModule
PostUpdateRequestCache - HttpModule
EndRequest - HttpModule
PreSendRequestHeaders - HttpModule
PreSendRequestContent - HttpModule