event to be triggered after login

When using the login wizard, how do I run an event that I want after the user logs in?

I used onauthenticate but that makes me unable to login (with this attribute I get an error message saying login was unsuccessful)

Is this the way to go or should I use another attibute or what?

I also used OnLoggedIn but that does not trigger the event...

<asp:Login ID="Login1" runat="server" OnLoggedIn="onLogin" ></asp:Login>

should trigger:

protected void onLogin(object sender, EventArgs e)
{
var r = System.Web.HttpContext.Current.User.Identity.Name;
int i = mmm.addLoggedIn(r);
Response.Write(r);
Response.Write(r);
Response.Write(r);
}