How to pass object of a class to stored procedure(in oracle)?

How to pass object of a class to stored procedure(in oracle)?

class:
public class clsPayrollEmployee
{
string _firstname;
string _lastname;
string _contactno;
string _email;
string _address;
public string firstname{
get { return _firstname; }
set { _firstname = value; }
}
public string lastname{
get { return _lastname; }
set { _lastname = value; }
}
public string contactno{
get { return _contactno; }
set { _contactno = value; }
}
public string email{
get { return _email; }
set { _email = value; }
}
public string address{
get { return _address; }
set { _address = value; }
}
}

Stored Procedure(oracle):
CREATE OR REPLACE procedure Payroll_Employee_Insert(firstname_ varchar2,lastname_ varchar2,contactno_ varchar2,email_ varchar2,address_ varchar2)
is
begin
insert into payroll_employee(firstname,lastname,contactno,email,address) values(firstname_,lastname_,contactno_,email_,address_);
end;
/

Insert Button Code:
protected void btnadd_Click(object sender, EventArgs e)
{
Entity ent = new Entity();
PAYROLL_EMPLOYEE emp = new PAYROLL_EMPLOYEE();
clsPayrollEmployee clsobj = new clsPayrollEmployee();
clsobj.firstname = txtfirstname.Text;
clsobj.lastname = txtlastname.Text;
clsobj.contactno = txtcontactno.Text;
clsobj.email = txtemailid.Text;
clsobj.address = txtaddress.Text;

ent.Insert_Emp(clsobj.firstname,clsobj.lastname,clsobj.contactno,clsobj.email,clsobj.address);
ent.SaveChanges();
}

instead of parameter of object i want to pass whole object to stored procedure