ASP. NET page event execution sequence is described

  • 2020-06-03 06:13:53
  • OfStack

  #region  Control event   The first 6 step  
  protected void Button1_Click(object sender, EventArgs e) 
  // Use these events to handle specific control events, such as  Button  The control of  Click  Event or  TextBox  The control of  TextChanged  Events.  
  // Pay attention to  
  // In a postback request, check if the page contains validator controls before performing any processing  Page  And each validation control  IsValid  Properties.  
  #region OnLoadComplete  The first 7 step  
  protected override void OnLoadComplete(EventArgs e) 
  // Use this event for tasks that need to load all other controls on the page.  
  #region OnPreRender  The first 8 step  
  protected override void OnPreRender(EventArgs e) 
  // Prior to the incident:  
  //Page  Object is called for each control and page  EnsureChildControls .  
  // Set up  DataSourceID  Each data-bound control of a property is called  DataBind  Methods. For more information, see data binding events for data bound controls below.  
  // Every control on the page occurs  PreRender  Events. Use this event to make last changes to the contents of a page or its controls.  
  #region SaveStateComplete  The first 9 step  
  protected override void OnSaveStateComplete(EventArgs e) 
  // Saved for the page and all controls before this event occurs  ViewState . Any changes made to the page or control at this time are ignored.  
  // Use this event to perform a task that meets the requirement that view state has been saved but that no changes have been made to the control.  
  #region Render  The first 10 step  
  // This is not an event; At this stage of processing, Page  Object calls this method on each control. all  ASP.NET Web  Both server controls 1 A control tag that is used to write and send to the browser  Render  Methods.  
  // If you create a custom control, you typically override this method to output the tag of the control. However, if the custom control only merges the standard  ASP.NET Web  Server control, which does not incorporate custom tags, does not need to be overridden  Render  Methods. For more information, see Developing Customizations  ASP.NET  Server controls.  
  // User control ( .ascx  File), so you don't need to explicitly render the control in your code.  
  #region OnUnload  The first 101 step  
  protected override void OnUnload(EventArgs e) 
  // This event occurs first for each control and then for the page. In a control, use this event to perform a final cleanup of a specific control, such as closing a control-specific database connection.  
  // For the page itself, use this event to perform final cleanup, such as closing open files and database connections, or completing logging or other requested specific tasks.  
  // Pay attention to  
  // During the unload phase, the page and its controls are rendered, so the response flow cannot be processed 1 Step change. If you try to call a method (such as  Response.Write  Method, the page will throw an exception.  

When the page is postback, such as clicking the button, the above events will be executed once again. At this time, the execution order is:
1. OnPreInit
2. OnInit
3. OnInitComplete
4. OnPreLoad
5. Page_Load
6. OnLoad
7. Button_Click
8. OnLoadComplete
9. OnPreRender

Related articles: