选中asp：checkbox中的复选框时，不会触发OnCheckedChanged事件

Question

There is a nested repeater in my work. I'm responsible to add asp:checkbox on every underneath repeater item, so that we can control each item by checkbox.

The markup code is:

<ItemTemplate>
  <li class="<%# GetCategoryClass(Container.DataItem) %> cl-li">    
    <asp:CheckBox runat="server" ID="checkBox" AutoPostBack="true" OnCheckedChanged="CheckedChanged" />
    <a class="cl-a excludeLink" visible='<%# GetCategoryClass(Container.DataItem) == "DISPLAYED" %>' href="<%# GetExcludeCategoryCommand(Container.DataItem) %>" runat="server" id="butExclude">x</a>
    <a class="cl-a" href="<%# GetCategoryCommand(Container.DataItem) %>" runat="server" id="butCategory"><%# GetCategoryTitle(Container.DataItem, true) %></a>
  </li>
</ItemTemplate>

The c# code is:

protected void CheckedChanged(object obj, EventArgs e)
{
    // some works    
}

I start to work on this problem and find the CheckedChanged function isn't fired via debugging. But, when I add a line in

if(IsPostBack){
   CheckedChanged(sender, e);  //add
}

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?

Answer 1

Your code should work. It depends how you wrote it.

I made a example which works :

Default.aspx :

<table>
<asp:Repeater ID="RepeaterCB" runat="server">
<ItemTemplate>
     <tr>
         <td><%# Container.DataItem %></td>
         <td><asp:CheckBox runat="server" OnCheckedChanged="OnCheckedChange" AutoPostBack="true"/></td>
      </tr>
</ItemTemplate>
</asp:Repeater>
</table>

Default.aspx.cs :

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        RepeaterCB.DataSource = new List<string> { "tom", "fred", "pijule" };
        RepeaterCB.DataBind();
    }

}

protected void OnCheckedChange(object sender, EventArgs e)
{
    Response.Write("<script>alert('Fire');</script>");
}

This code fires an alert each time I check or uncheck a textbox.

Hope it helps.