ASP.NET Web Forms — Page Life Cycle, ViewState, Controls and State Management Cheat Sheet

ASP.NET Web Forms — Page Life Cycle, ViewState, Controls and State Management

How ASP.NET Web Forms works inside IIS (application and page life cycle), folder structure (App_Code, App_Data, App_Start, Bin, App_Themes), Web Site vs Web Application projects, .aspx/.aspx.cs code-behind, server controls and events, PostBack and ViewState, state management (ViewState, ControlState, Session, Application, Cache, cookies, query strings, hidden fields), validation controls, master pages, user controls and custom controls, data binding with GridView/Repeater and SqlDataSource vs ObjectDataSource, Global.asax and web.config, Forms authentication, custom errors, performance and migrating Web Forms to ASP.NET Core.

Page life cycle

PreInit → Init → InitComplete → (LoadViewState, LoadPostData) → PreLoad → Load → control events → LoadComplete → PreRender → SaveStateComplete → Render → Unload.

Application pipeline

BeginRequest → Authenticate → Authorize → ResolveRequestCache → AcquireRequestState → PreRequestHandlerExecute → handler (Page) → PostRequestHandlerExecute → ReleaseRequestState → UpdateRequestCache → EndRequest.

State options

Page: ViewState/ControlState/hidden field · request: query string · browser: cookies · user: Session (InProc/StateServer/SQL/Redis) · all users: Application/Cache.

Folders & files

App_Code · App_Data · App_Start · App_Themes · App_GlobalResources · bin · .aspx + .aspx.cs + .designer.cs · .master · .ascx · .ashx · Global.asax · Web.config (+ transforms).

Errors

try/catch → Page_Error → Application_Error (log) → customErrors/httpErrors (friendly pages) · never debug="true" or customErrors="Off" in production.