ASP.Net: click event for dynamic button in dynamically created nested update panel is not raised

Question

I have UpdatePanel with button.

<asp:UpdatePanel runat="server" ID="upOuter" UpdateMode="Conditional">
    <ContentTemplate>
        <asp:Button ID="btnNestInnerPanel" runat="server" 
        OnClick="btnNestInnerPanelClick" Text="Nest Update Panel" />
    </ContentTemplate>
</asp:UpdatePanel>

I want to nest inner updatepanel with other button in outer updatepanel by click that button. And I want to update inner updatepanel by click new button. Page has such behind code:

public partial class _Default : Page
{
    private Button btnInner;

    protected void Page_Load(object sender, EventArgs e)
    {
        btnInner = new Button { Text = "Click Me", ID = "MyId" };
        btnInner.Click += btnInnerClick;
    }

    protected void btnNestInnerPanelClick(object sender, EventArgs e)
    {
        UpdatePanel upInner = new UpdatePanel();
        upInner.UpdateMode = UpdatePanelUpdateMode.Conditional;
        upInner.ContentTemplateContainer.Controls.Add(btnInner);
        upOuter.ChildrenAsTriggers = false;
        upOuter.ContentTemplateContainer.Controls.Add(upInner);
    }

    private void btnInnerClick(object sender, EventArgs e)
    {
        Button btn = (Button)sender; 
    }
}

When I click first button, it causes update of panel and inner panel appears. That's correct. But if I click newly created button in inner panel, btnInnerClick handler is not raised. Does anybody know what's problem?

If I nest dynamically inner updatepanel in simple placeholder (not in outer updatepanel), btnInnerClick handler is raised correctly. I have no idea...

Answer 1

all ASP.Net dynamic controls must be re-created on page load in order to properly have their events called. Google: ASP.Net Page Lifecycle and Dynamic Controls...

https://web.archive.org/web/20210330142645/http://www.4guysfromrolla.com/articles/092904-1.aspx