Pfthb

I have written a procedure-

create or replace procedure cv(x in int,y in int,z in varchar)
as
cursor c
is
select email,collegename,cgpa,compname
from student_cv
where (cgpa>=x and yearsofexp>=y) and compname=z;
tem c%rowtype;
begin
open c;
loop
fetch c into tem;
exit when c%notfound;
insert into temp values(tem.email,tem.collegename,tem.cgpa,tem.compname);
end loop;
end;
/

and now based on two combo box values(which the user inputs) and 1 local string constitute the parameters passed to my procedure.

This is the code I am using-

 //DB_connect();
 string oracleb = "Data source=HPPRO58; user ID=system; password=deb;";
 conn = new OracleConnection(oracleb);
 //conn.Open();
 conn.Open();
 String x3 = "google";
 String x1 ;
 String x2;
 String s1 = "delete from temp";
 OracleCommand comm = new OracleCommand(s1, conn);
 comm.ExecuteNonQuery();

 // System.Data.OracleClient.OracleCommand comm2 = new System.Data.OracleClient.OracleCommand();
 OracleCommand comm2 = new OracleCommand();
 String s2 = "cv";
 comm2.Connection = conn;
 comm2.CommandText = s2;
 comm2.CommandType = CommandType.StoredProcedure;
 comm2.Parameters.Add("x", System.Data.OracleClient.OracleType.Number).Value = comboBox1.Text;
 comm2.Parameters.Add("y", System.Data.OracleClient.OracleType.Number).Value = comboBox2.Text;
 comm2.Parameters.Add("z", System.Data.OracleClient.OracleType.VarChar).Value = x3;
 //comm.Parameters.Add("x", OracleType.Number).Value = comboBox1.Text;
 comm2.ExecuteNonQuery();

 String s3 = "select * from temp";
 OracleCommand comm3 = new OracleCommand(s3, conn);
 OracleDataAdapter MyAdapter3 = new OracleDataAdapter();//adapter acts as interface btw database and dataset(which is collectio of tables)
 MyAdapter3.SelectCommand = comm;
 DataTable dTable3 = new DataTable();//datatable represents a single table in database 
 MyAdapter3.Fill(dTable3);
 dataGridView1.DataSource = dTable3;
 conn.Close();

but on running this code the error displayed is -

and line 59 is -

 comm2.Parameters.Add("x", System.Data.OracleClient.OracleType.Number).Value = comboBox1.Text;

therefore I think there is some problem in declaring the parameters in my code