insert into database

Question

I want to insert a record into database and display into gridview
but i am getting error
 
 protected void btnsubmit_Click(object sender, EventArgs e)
        {
            cmp c = new cmp();
            c.EmpName = txtempname.ToString();
            c.jobid = Convert.ToInt32(txtjobid.Text);
            c.managerid = Convert.ToInt32(txtmanagerid.Text);
            c.salary = Convert.ToInt32(txtsalary.Text);
            c.hiredate = Convert.ToDateTime(txthiredate.Text);
            Employee a = new Employee();
            a.insertEmployeeData(c);
        }

 in DAl

  public void insertEmployeeData(cmp c)
        {
            CompanyDataContext db = new CompanyDataContext();
            var list = db.Employees.Where(p => p.empid == c.Employeeid).FirstOrDefault();
            list.empname = c.EmpName;
            list.jobid = c.jobid;
            list.hiredate = c.hiredate;
            list.salary = c.salary;
            list.managerid = c.managerid;
            db.Employees.InsertOnSubmit(list);
            db.SubmitChanges();
        }

 

Object reference not set to an instance of an object.

list.empname = c.EmpName;
here i am getting error
plz help
me thanq.