This class is a custom System.EventArgs that is used in the event handler for the FormsAuthenticationModule.Authenticate event. It provides two properties: Context, which provides a reference to the current System.Web.HttpContext, and User, which will be a null reference because information is not yet retrieved from the Forms authentication cookie. This event is not typically used because Forms authentication already uses the custom code you have created for the login page.
public sealed class FormsAuthenticationEventArgs : EventArgs { // Public Constructors public FormsAuthenticationEventArgs(System.Web.HttpContext context); // Public Instance Properties public HttpContext Context{get; } public IPrincipal User{set; get; } }