title: OnCheckedChanged event doesn't fire when check the checkbox in asp:checkbox
body: <p>There is a <strong>nested repeater</strong> in my work. I'm responsible to add asp:checkbox on every underneath repeater item, so that we can control each item by checkbox.</p>
  
  <p>The markup code is:</p>
  
  <pre><code>&lt;ItemTemplate&gt;
    &lt;li class="&lt;%# GetCategoryClass(Container.DataItem) %&gt; cl-li"&gt;    
      &lt;asp:CheckBox runat="server" ID="checkBox" AutoPostBack="true" OnCheckedChanged="CheckedChanged" /&gt;
      &lt;a class="cl-a excludeLink" visible='&lt;%# GetCategoryClass(Container.DataItem) == "DISPLAYED" %&gt;' href="&lt;%# GetExcludeCategoryCommand(Container.DataItem) %&gt;" runat="server" id="butExclude"&gt;x&lt;/a&gt;
      &lt;a class="cl-a" href="&lt;%# GetCategoryCommand(Container.DataItem) %&gt;" runat="server" id="butCategory"&gt;&lt;%# GetCategoryTitle(Container.DataItem, true) %&gt;&lt;/a&gt;
    &lt;/li&gt;
  &lt;/ItemTemplate&gt;
  </code></pre>
  
  <p>The c# code is:</p>
  
  <pre><code>protected void CheckedChanged(object obj, EventArgs e)
  {
      // some works    
  }
  </code></pre>
  
  <p>I start to work on this problem and find the CheckedChanged function isn't fired via debugging. But, when I add a line in</p>
  
  <pre><code>if(IsPostBack){
     CheckedChanged(sender, e);  //add
  }
  </code></pre>
  
  <p>It works and goes into CheckedChanged function when I debug.
  I have read many articles, none of them say I need to add that line in IsPostBack block. Is there anyone can show me the principle of that?</p>