Suppress Page_Init after authentication

 Hello,
I have a .aspx site with 3 GridViews. These GridViews are filled by a database on a onClick() without a authentication. When a User logged in now the GridViews are empty, because the Loggin Controll makes a Page_Init. How can I supress the Page_Init or save the current state of the GridViews and restore this after the Loggin?
 After the authentication the user have a "Detail-View" of a row of a GridView. I use the Loggin Controll and have the Login_Authenticate(object sender, AuthenticateEventArgs e) implemented for a authentication against a database.

 
I hope someone can help me 
ChriZ
 
 I use:

.NET 3,5
VS2008

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