向线程方法传递参数

private void bindCourse()
        {
            if (cmbSpecity.SelectedValue != null)
            {
                int spid = (int)cmbSpecity.SelectedValue;
                Thread thread = new Thread(threadCourse);
                thread.Start(spid); //传递参数
            }
            else
            {
                _dtCourse = null;
            }
        }

        private void threadCourse(object spid)//接收参数的线程
        {
            Course cour = new Course();
            Specialty info = new Specialty();
            info.ID = (int)spid;
            _dtCourse = cour.List(info);
            cmbCourse.Invoke(_getCourse, _dtCourse);
        }

        private void setCourse(object objData)//委托方法
        {
            DataTable dt = (DataTable)objData;
            cmbCourse.DisplayMember = "title";
            cmbCourse.ValueMember = "id";
            cmbCourse.DataSource = dt;
        }