protected void InitializeModalDropDownSupervisor()
        {
            int userid = Convert.ToInt32(modalDropDownUsers.SelectedItem.Value);
            int deptid = Convert.ToInt32(modalDropDownDepartment.SelectedItem.Value);
            User user = new User();
            var data = user.GetAvailableSupervisors(userid, deptid);

            modalDropDownSupervisor.DataSource = data;
            for (int i = 0; i < gridViewModal.Rows.Count; i++)
            {
                Label labelSupId = (Label)gridViewModal.Rows[i].FindControl("modalLabelSupId");
                int lid = Convert.ToInt32(labelSupId.Text);
                for (int j = 0; j < data.Count; j++)
                {
                    if (data[j].Id == lid)
                    {
                        data.RemoveAt(j);
                        break;
                    }
                }
            }
            modalDropDownSupervisor.DataTextField = "fullname";
            modalDropDownSupervisor.DataValueField = "Id";
            modalDropDownSupervisor.DataBind();
            if (modalDropDownSupervisor.Items.Count < 1)
                modalBtnAdd.Visible = false;
            else
                modalBtnAdd.Visible = true;
        }