How to access controls in  HeaderTemplate and FooterTemplate

We are using ASP .NET, C# here in this example.

Lets take this repeater as an example. 

<asp:Repeater ID="rpt" runat="server">
    <HeaderTemplate>
       <asp:CheckBox ID="chk1" runat="server" />
    </HeaderTemplate>
    <ItemTemplate>
       HELLO
    </ItemTemplate>
    <FooterTemplate>
       <asp:CheckBox ID="chk2" runat="server" />
    </FooterTemplate>
</asp:Repeater>

You can access the header and footer item controls on ItemCreated or even ItemDataBound. But not when you iterate through the repeater items like this:

foreach(RepeaterItem ri in rpt.Items)

{
    if (ri.ItemType == ListItemType.Header)
    {
        CheckBox chk1 = (CheckBox)ri.FindControl("chk1");

       chk1.Checked=true;
    }
    if (ri.ItemType == ListItemType.Footer)
    {
        CheckBox chk2 = (CheckBox)ri.FindControl("chk2");

       chk2.Checked=true;
    }
}

This will simply not work.

Without going through the explanation why it does not work, let see how we can get it work.

If you have a footer and header template defined in the repeater, header is item with index 0 and footer is the last item. Bearing that in mind, we can simply access the header and footer controls as follows:

CheckBox chk1 = (CheckBox)rpt.Controls[0].FindControl("chk1");
chk1.Checked = true;
CheckBox chk2 = (CheckBox)rpt.Controls[rpt.Controls.Count - 1].FindControl("chk2");
chk2.Checked = true;