ASP.NET Code Example


using System;

namespace myProject
    public partial class WebForm1 : System.Web.UI.Page
        public string PageSteps = string.Empty;

        //Raised after the start stage is complete and before the initialization stage begins.
        protected void Page_PreInit(object sender, EventArgs e)
            PageSteps += "1 - Page_PreInit<br>";

            //Access to page Controls not available in this step
            //Label1.Text = "Step 1";

        //Raised after all controls have been initialized and any skin settings have been applied.
        //The Init event of individual controls occurs before the Init event of the page.
        protected void Page_Init(object sender, EventArgs e)
            PageSteps += "2 - Page_Init<br>";

            Label1.Text = "Step 2";

        //Raised at the end of the page's initialization stage.
        //Only one operation takes place between the Init and InitComplete events: tracking of view state changes is turned on.
        //View state tracking enables controls to persist any values that are programmatically added to the ViewState collection.
        //Until view state tracking is turned on, any values added to view state are lost across postbacks.
        //Controls typically turn on view state tracking immediately after they raise their Init event.
        protected void Page_InitComplete(object sender, EventArgs e)
            PageSteps += "3 - Page_InitComplete<br>";

            Label1.Text = "Step 3";

        //Raised after the page loads view state for itself and all controls, and after it processes postback data that is included with the Request instance.
        protected override void OnPreLoad(EventArgs e)
            PageSteps += "4 - OnPreLoad<br>";

            Label1.Text = "Step 4";

        //The Page object calls the OnLoad method on the Page object, and then recursively does the same for each child control until the page and all controls are loaded.
        //The Load event of individual controls occurs after the Load event of the page.
        protected void Page_Load(object sender, EventArgs e)
            PageSteps += "5 - Page_Load<br>";

            Label1.Text = "Step 5";

        //Use these events to handle specific control events, such as a Button control's Click event or a TextBox control's TextChanged event.
        protected void btnSubmit_Click(object sender, EventArgs e)
            //Step only visible on PostBack
            PageSteps += "6 - btnSubmit_Click<br>";

            Label1.Text = "Step 6";

        //Raised at the end of the event-handling stage.
        protected void Page_LoadComplete(object sender, EventArgs e)
            PageSteps += "7 - Page_LoadComplete<br>";

            Label1.Text = "Step 7";

        //Raised after the Page object has created all controls that are required in order to render the page, including child controls of composite controls.
        //(To do this, the Page object calls EnsureChildControls for each control and for the page.)
        protected override void OnPreRender(EventArgs e)
            PageSteps += "8 - OnPreRender<br>";

            Label1.Text = "Step 8";

        //Raised after each data bound control whose DataSourceID property is set calls its DataBind method.
        protected override void OnPreRenderComplete(EventArgs e)
            PageSteps += "9 - OnPreRenderComplete<br>";

            Label1.Text = "Step 9";

        //Raised after view state and control state have been saved for the page and for all controls.
        //Any changes to the page or controls at this point affect rendering, but the changes will not be retrieved on the next postback.
        protected override void OnSaveStateComplete(EventArgs e)
            PageSteps += "10 - OnSaveStateComplete<br><hr><br>";

            Label1.Text = "Step 10";

        // Render
        //This is not an event; instead, at this stage of processing, the Page object calls this method on each control.
        //All ASP.NET Web server controls have a Render method that writes out the control's markup to send to the browser.

        //Raised for each control and then for the page.
        //Controls use this event to do final cleanup for specific controls, such as closing control-specific database connections
        protected void Page_UnLoad(object sender, EventArgs e)
            //This last PageSteps addition will not be visible on the page
            PageSteps += "11 - Page_UnLoad<br>";

            //Access to page Controls not available in this step
            //Label1.Text = "Step 11";      

Add the following code to the .aspx page to visualize the Steps in the Life Cycle.

<b>Page Life Cycle Visualization:</b>
<br />
<%= PageSteps %>

enter image description here

More information