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.

Vulpes · Answer

Yes Sam's right. The FirstOrDefault() extension method will return null if there's no record for which p.empid == c.Employeeid. So as 'c' can't be null 'list' must be null and the remainder of the method should only be executed if it's not null to avoid the exception.

Sam Hobbs · Answer

When you get that error look at the code during debugging to see what field is the problem. If you get the error when you are not debugging then execute it again with the debugger. In this case probably list is null and you can verify that in the debugger. So I assume that there the Employee id does not exist. You should add code to handle the situation where the Employee id does not exist.