How refresh gridview dropdownlist

See more:

C#5.0

i have a dropdownlist in webform,my requirement are followings
1.there are three column label pointname,Employee dropdownlist,and checkbox
2.when Employee is selected from list it will remove employee through selected index change.
3.when employee is removed i want that dropdownlist updated, each time when employee is removed?
these are two code snippet

protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
       {
           if (e.Row.RowType == DataControlRowType.DataRow)
           {

               CheckBox CHKBOX = (e.Row.FindControl("Released") as CheckBox);
               CheckBox CHKBOX1 = (e.Row.FindControl("Released1") as CheckBox);
               DropDownList ddlEmployee = (e.Row.FindControl("ddlEmp") as DropDownList);
               DropDownList ddlEmployee2 = (e.Row.FindControl("ddlEmp2") as DropDownList);
               var Emplist1 = _service.GetAllSectorEmployee();
               var lastrecord = _service.GetAllDailyManualRoaster().LastOrDefault(x => x.ManDailyRoasterDate == DateTime.Now.Date);
               var lastrecord2 = _service.GetAllDailyManualRoaster().LastOrDefault(x => x.ManDailyRoasterDate == DateTime.Now.Date);
               ddlEmployee.Bind(Emplist1, "EmployeeIdName", "Employee_Id");
               ddlEmployee2.Bind(Emplist1, "EmployeeIdName", "Employee_Id");

           }
       }
  private void BindGrid()
       {
           Entities entities = new Entities();


           Gridview1.DataSource = (from customer in entities.SectorWisePoints
                                  join se in entities.SectorEmployees on customer.Sector_Id equals se.Sector_Id
                                  select new
                                  {

                                      customer.Name

                                  }).ToList();

           Gridview1.DataBind();


       }