public void FormsAuthentication_OnAuthenticate ( object src, FormsAuthenticationEventArgs args ) {
   if ( FormsAuthentication.CookiesSupported ) {
      if ( Request.Cookies[FormsAuthentication.FormsCookieName] != null ) {
         try {
            FormsAuthenticationTicket ticket = FormsAuthentication.Decrypt (
               Request.Cookies [ FormsAuthentication.FormsCookieName ].Value );
            args.User = new System.Security.Principal.GenericPrincipal (
               new Samples.AspNet.Security.MyFormsIdentity ( ticket ), new string [ 0 ] );
         }
         catch ( Exception e ) {
            // Decrypt method failed.
         }
      }
   } else {
      throw new HttpException ( "Cookieless Forms Authentication is not " +
         "supported for this application." );
   }
}

Public Sub FormsAuthentication_OnAuthenticate ( src As Object, args As FormsAuthenticationEventArgs )
   If FormsAuthentication.CookiesSupported Then
      If Not Request.Cookies ( FormsAuthentication.FormsCookieName ) Is Nothing Then
         Try
            Dim ticket As FormsAuthenticationTicket = FormsAuthentication.Decrypt ( _
               Request.Cookies ( FormsAuthentication.FormsCookieName ) .Value )
            args.User = New System.Security.Principal.GenericPrincipal ( _
               New Samples.AspNet.Security.MyFormsIdentity ( ticket ), New String ( 0 ) { } )

         Catch e As HttpException
            ' Decrypt method failed.
         End Try
      End If
   Else
      Throw New Exception ( "Cookieless Forms Authentication is not " & _
         "supported for this application." )
   End If
End Sub