C# - Button In Repeater Not Raising Event?

When I work with the tab Ajax control, and in one tab, I have a Repeater: <asp:Repeater runat="server" ID="rp1" onitemcommand="rp1_ItemCommand"> and in protected void rp1_ItemCommand(object source, RepeaterCommandEventArgs e) method, I add a button and it's event:

Button btn = new Button();
btn.Text = "Update";
btn.Click += new EventHandler(btn_Click);
((Repeater)source).Items[0].Controls.Add(btn);
void btn_Click(object sender, EventArgs e)
{
Response.Redirect("http://google.com");
}

However, when I click on the update button, the event is not raised.