Crystalreportviewer in webmethod not working

it shows error "Object reference not set to an instance of object" i am trying to generate the crystal report by using ajax and jquery in webmethod but method is static hence i cant find the id of crystalreportviewer in webmethod. Hence i use httpcontext method to find the id but its not working.any other way to find the crystalreportviewer in webmethod. How to solve.Thanks in advance

Quote:

Jquery:- $(document).ready(function () {
$("#btn").click(function () {
var croidforprint = 'SSPL/DEL/LINER/CRO/12-16/002';
$.ajax({
url: "TestCrystallWithAjax.aspx/DOPrint",
type: "Post",
dataType: "json",
data: '{enqcode: ' + JSON.stringify(croidforprint) + '}',
contentType: "application/json; charset=utf-8",
success: function (data) {
alert("Hello");
},
error: function (XMLHttpRequest, textStatus, errorThrown) {
debugger;
alert("Error while retrieving data of :" + textStatus); alert("Error: " + XMLHttpRequest.responseText);
}
});

});
});
HTML:-

<input type="button" id="btn" value="print" />
<cr:crystalreportviewer id="CrystalReportViewer1" runat="server" autodatabind="true">

C# Webmethod:-
[WebMethod]
public static void DOPrint(string enqcode)
{
string cs = ConfigurationManager.ConnectionStrings["DUM01"].ConnectionString;
using (var scon = new SqlConnection(cs))
{
using (var cmd = new SqlCommand())
{
cmd.CommandText = "select CROID,DODate,DOValidity,PrincipleName,AgentName,LoadPort,DischargePort,DeliveryPort,VesselName,VoyageNumber,ETA,ETD,LinerCode,VIANo,ROTNo ,CutOffDate,CutOffTime,VGMDate,VGMTime,AgentCode,BrokerName,YardName,YardAddress1,YardAddress2,YardTelNo,From13Name,From13Address1,Form13Address2,Form13TelNo,CustomerName from CROFormTbl where CROID='" + enqcode + "'";
cmd.CommandType = CommandType.Text;
cmd.Connection = scon;
scon.Open();
SqlDataReader sdr = cmd.ExecuteReader();
if (sdr.Read())
{
ReportDocument dopart = new ReportDocument();
string reportPath = HttpContext.Current.Server.MapPath("CrystallReports\\DOReport.rpt");
dopart.Load(reportPath);
dopart.SetParameterValue("Doid", sdr.GetValue(0).ToString());
dopart.SetParameterValue("DODate", sdr.GetValue(1).ToString());
dopart.SetParameterValue("Validity", sdr.GetValue(2).ToString());
dopart.SetParameterValue("PrincipleName", sdr.GetValue(3).ToString());
dopart.SetParameterValue("AgentName", sdr.GetValue(4).ToString());
dopart.SetParameterValue("LoadPort", sdr.GetValue(5).ToString());
dopart.SetParameterValue("DischargePort", sdr.GetValue(6).ToString());
dopart.SetParameterValue("DeliveryPort", sdr.GetValue(7).ToString());
dopart.SetParameterValue("VesselName", sdr.GetValue(8).ToString());
dopart.SetParameterValue("VoyageNumber", sdr.GetValue(9).ToString());
dopart.SetParameterValue("ETA", sdr.GetValue(10).ToString());
dopart.SetParameterValue("ETD", sdr.GetValue(11).ToString());
dopart.SetParameterValue("LinerCode", sdr.GetValue(12).ToString());
dopart.SetParameterValue("VIANo", sdr.GetValue(13).ToString());
dopart.SetParameterValue("ROTNo", sdr.GetValue(14).ToString());
dopart.SetParameterValue("CutOffDate", sdr.GetValue(15).ToString());
dopart.SetParameterValue("CutOffTime", sdr.GetValue(16).ToString());
dopart.SetParameterValue("VGMDate", sdr.GetValue(17).ToString());
dopart.SetParameterValue("VGMTime", sdr.GetValue(18).ToString());
dopart.SetParameterValue("AgentCode", sdr.GetValue(19).ToString());
dopart.SetParameterValue("BrokerName", sdr.GetValue(20).ToString());
dopart.SetParameterValue("YardName", sdr.GetValue(21).ToString());
dopart.SetParameterValue("YardAddress1", sdr.GetValue(22).ToString());
dopart.SetParameterValue("YardAddress2", sdr.GetValue(23).ToString());
dopart.SetParameterValue("YardTelNo", sdr.GetValue(24).ToString());
dopart.SetParameterValue("From13Name", sdr.GetValue(25).ToString());
dopart.SetParameterValue("From13Address1", sdr.GetValue(26).ToString());
dopart.SetParameterValue("Form13Address2", sdr.GetValue(27).ToString());
dopart.SetParameterValue("Form13TelNo", sdr.GetValue(28).ToString());
dopart.SetParameterValue("CustomerName", sdr.GetValue(29).ToString());
if (HttpContext.Current != null)
{
Page page = (Page)HttpContext.Current.Handler;
CrystalReportViewer cry = (CrystalReportViewer)page.FindControl("CrystalReportViewer1");
cry.ReportSource = dopart;
cry.DataBind();
}

}
scon.Close();
}
}
}