one solution is you can use integrated security =true; while making crystal report...
Session["Rpt"] = "CR_Member_payment_status.rpt";
Session["Rpt_ds"] = ul.usp_fill_member_paydetail();
string url = "report.aspx";
string fullURL = "window.open('" + url + "', '_blank', 'height=500,width=800,status=yes,toolbar=no,menubar=no,location=no,scrollbars=yes,resizable=no,titlebar=no' );";
ScriptManager.RegisterStartupScript(this, typeof(string), "OPEN_WINDOW", fullURL, true);
here
ul is object of class userlist
and
usp_fill_member_paydetail();
is a method returns a data set...
try this...at your btn_show click...
report will not ask for username and password