title: Two types of postback events
body: <p><br /></p>
  
  <p>1) I found two articles, each categorizing a bit differently the two types of postback events:</p>
  
  <blockquote>
    <p>One resource says the two types of postback events are <strong>Changed</strong> event ( where controls implement IPostbackDataHandler ), which fires when data is changed between postbacks, and then are <strong>Raised</strong> events ( where controls implement IPostbackEventHandler ), which are raised by server controls for whatever reason the control sees fit </p>
    
    <p>Other article says the two types are <strong>Immediate response</strong> events and <strong>Change</strong> events. According to this article, Immediate response events are ones that actually trigger a postback</p>
  </blockquote>
  
  <p><br /></p>
  
  <p>a) Which categorization is correct?</p>
  
  <p>b) If second article was correct, then if TextBox control had AutoPostBack=”true”, shouldn’t then TextChanged  also be considered Immediate response event?</p>
  
  <p><br /></p>
  
  <p>2) When page is submitted back to the server due to some user action,  <em>then at Event handling stage</em>, ASP.NET raises events of all controls that got their data changed since the last postback. The event that actually triggered a postback ( such as Click event ) is raised last</p>
  
  <p><br /></p>
  
  <p>a) But what if user selecting a row in GridView caused a postback? When GridView causes a postback due to Row selection, then unlike simpler controls ( like TextBox or Button ), that postback causes GridView to fire not one, but several server-side events during Event handling stage ( SelectedIndexChaning and SelectedIndexChanged). </p>
  
  <p>Which of these GridView’s events is considered by ASP.NET to be the one that caused a postback? </p>
  
  <p><br /></p>
  
  <p>thank you</p>