How to check null field column using C# in ASP.Net MVC

Ruben12345 says:

if id 1 & field end_date_assignment = null 
then end_date_assignment fill with new create with  contain same id

 can you explain last statement in more detail?

i have a table with name shipment_assignment

with contain field table :

id, member_id, partner_id, vehicle_id, shipment_no, begin_date_time, end_date_time, active

note * end_date_time (allow null) , id (identity)

first step :

 i have add new record from csharp asp. mvc code

  id = 12

  member_id= 22

  partner_id = 32

  vehicle_id  = 42

  shipment_no = 52

  begin_date_time = 2017-04-13

  end_date_time   = null

  active = 1

second step

  i add one more record with contain same vehicle_id :

  id = 13

  member_id= 22

  partner_id = 32

  vehicle_id  = 42

  shipment_no = 53

  begin_date_time = 2017-04-13

  end_date_time   = null

  active = 1

When i have insert new record with same vehicle_id then end_date_time with contain empty/null (from first step) must be inserted value  from begin_date_time at second step

 Here's My Code

 [HttpPost]
        public ActionResult Add([ModelBinder(typeof(DevExpressEditorsBinder))] ShipmentAssigmentModel model)
        {
            int memberId = ((CustomIdentity)User.Identity).MemberId;
            if (ModelState.IsValid)
            {
                //  get vehicle 
                ShipmentAssignment getvehicle = db.ShipmentAssignments.Where(m => m.member_id == memberId
                                                                           && m.partner_id == model.partner_id && m.vehicle_id == model.vehicle_id && m.end_date_time ==model.end_date_time).FirstOrDefault();

                //check if duplicate shipment number
                //ShipmentAssignment getshipment_number = db.ShipmentAssignments.Where(m => m.member_id == memberId
                //                                                           && m.partner_id == model.partner_id && m.shipment_no == model.shipment_no).FirstOrDefault();




                if (model.partner_id == null || model.partner_id < 1)
                {
                    // If Partner Not Choosen
                    ModelState.AddModelError("", "Partner Not Choosen");
                }

                // If VehicleId Not Choosen
                else if (model.vehicle_id == null || model.vehicle_id < 1)
                {
                    ModelState.AddModelError("", "Vehicle Not Choosen");
                }

                // if vehicle has been assigned but not closed
                //else if (getvehicle != null)
                //{
                //    ModelState.AddModelError("", "This Vehicle Has Been Assigned");
                //}

                // if shipment number active and Status = True
                //else if (getshipment_number != null & model.active != true)
                //{
                //    ModelState.AddModelError("", "Shipment Number HasBeen Assigned");
                //}

                // if string Shipment number is Empty
                else if (string.IsNullOrEmpty(model.shipment_no))
                {
                    
                    ModelState.AddModelError("", "Shipment Number Cannot Be Empty");
                }
                    // if start assignment is empty
                else if (string.IsNullOrEmpty(Convert.ToString(model.begin_date_time))) 
                {
                    ModelState.AddModelError("", "Start Assignment Date Cannot Be Empty");
                }

            }

            if (ModelState.IsValid)
            {

                ShipmentAssignment shipment = new ShipmentAssignment()
                {
                    member_id = memberId,
                    partner_id = (int)model.partner_id,
                    vehicle_id = (int)model.vehicle_id,
                    shipment_no = model.shipment_no,
                    begin_date_time = model.begin_date_time,
                    create_date = DateTime.Now,
                    active = true,
                    
                };

                db.ShipmentAssignments.Add(shipment);
                db.SaveChanges();
                //Session["UpdateMessage"] = "Vehicle has been assign";
                SetUpdateMessage("Vehicle has been assigned");
                return RedirectToAction("Index");
            }
            else
            {
                ViewBag.PartnerList = dbUtil.GetPartnerList(memberId, true);
                Session["VehicleId"] = model.vehicle_id;
                //GetVehicles();
                return View(model);
            }

        }

Ruben12345 says:

When i have insert new record with same vehicle_id then end_date_time with contain empty/null (from first step) must be inserted value  from begin_date_time at second step

 so you want to say that when you have inserted one record with end_date = null and vehicle id something and while inserting new record you want to check whether any record exists in ship table with inserting vehicle id if vehicle id exists then you want to insert the end time same as begin time ?

hi...AnandM.

yes, you are right.. may you give me some help

Hi Ruben12345,

You can achieve like below by checking whether the vehicleId already exists or not if exists then assign the end time with begin time and in else condition you need to add send end date null you can optimize your code according to your need i have just provided you the way how you can achieve your requirement.

ShipmentAssignment getduplicatevehicle = db.ShipmentAssignments.Where(m => m.vehicle_id == model.vehicle_id ).FirstOrDefault();
if (getduplicatevehicle != null)
{
    ShipmentAssignment shipment = new ShipmentAssignment()
    {
        member_id = memberId,
        partner_id = (int)model.partner_id,
        vehicle_id = (int)model.vehicle_id,
        shipment_no = model.shipment_no,
        begin_date_time = model.begin_date_time,
        create_date = DateTime.Now,
        end_date_time = model.begin_date_time,
        active = true

    };

    db.ShipmentAssignments.Add(shipment);
    db.SaveChanges();
    //Session["UpdateMessage"] = "Vehicle has been assign";
    SetUpdateMessage("Vehicle has been assigned");
    return RedirectToAction("Index");
}
else
{
    ShipmentAssignment shipment = new ShipmentAssignment()
    {
        member_id = memberId,
        partner_id = (int)model.partner_id,
        vehicle_id = (int)model.vehicle_id,
        shipment_no = model.shipment_no,
        begin_date_time = model.begin_date_time,
        create_date = DateTime.Now,        
        active = true

    };

    db.ShipmentAssignments.Add(shipment);
    db.SaveChanges();
    //Session["UpdateMessage"] = "Vehicle has been assign";
    SetUpdateMessage("Vehicle has been assigned");
    return RedirectToAction("Index");
}