How to handle ViewState Exception

HttpApplication httpApp = this.Context.ApplicationInstance;

HttpException httpEx = httpApp.Server.GetLastError() as HttpException;

if (httpEx != null)

{

    if (

        httpEx.WebEventCode == System.Web.Management.WebEventCodes.AuditInvalidViewStateFailure

        ||

        httpEx.WebEventCode == System.Web.Management.WebEventCodes.InvalidViewState

        ||

        httpEx.WebEventCode == System.Web.Management.WebEventCodes.InvalidViewStateMac

        ||

        httpEx.WebEventCode == System.Web.Management.WebEventCodes.RuntimeErrorViewStateFailure

        )

    {

        HttpContext.Current.ClearError();

        Response.Write("Error: An invalid viewstate has been detected (WebEventCode: " + httpEx.WebEventCode.ToString() + ").");

    }

}