protected void Button1_Click(object sender, EventArgs e)
        {
            UserInfo userinfo = new UserInfo();

            userinfo.UserName = "******";
            userinfo.UserId   = 1;
            userinfo.GroupId  = 1;
            FormsPrincipal <UserInfo> .SignIn("yanzhiwei", userinfo, 1);

            FormsPrincipal <UserInfo> .RedirectDefaultPage("yanzhiwei");
        }