Set Value for Filed on Condition in MVC

Question

I have three Tables in SQL with following fileds

1) Order : [OrderID (pk)], [OrderSize], [Thickness], [OD]

2) PipeAllocation : [PipeNo(PK)], [OrderID (fk)], [Length], [Status]

3) Process: [ProcessID (pk)], [PipeNo(fk)], [Date], [MPP]

for adding record in process table I want set value for MPP on criteria of Thickness so I write following code but I got error of "Object reference not set to an instance of an object.". I dont have any null value in thickness field.

my code is

[HttpPost]
public ActionResult CreateP3(Process process)
{
var tr = process.StageID + process.PIPENO + process.Status;
var checkme = (from x in db.Processes
where x.StageID + x.PIPENO + x.Status == tr && x.Status == "OK"
select x).ToList();
if (checkme.Count > 0)
{
ModelState.AddModelError("PIPENO", "You are trying Duplicate Pipe Entry");
}
if (ModelState.IsValid)
{
if (process.PipeAl.Order.THK > 1)
{
process.MPP = 10;
}
process.CuttingSpeed = (process.ActualMeter*1000)/process.CuttingTime;
db.Processes.Add(process);
db.SaveChanges();
return RedirectToAction("IndexP3");
}
var EmpAtnList = db.Attens.ToList();
IEnumerable<SelectListItem> AttnList = from s in EmpAtnList.OrderByDescending(s => s.ATTNDATE)
select new SelectListItem
{
Value = s.ATTNSYSID.ToString(),
Text = s.ATTNDATE + "--" + s.Emp.EmpName
};
ViewBag.ATTNSYSID = new SelectList(AttnList, "Value", "Text");
//ViewBag.ATTNSYSID = new SelectList(db.Attens, "ATTNSYSID", "EMPCODE", process.ATTNSYSID);
ViewBag.StageID = new SelectList(db.OMStages, "StageID", "StageName");
ViewBag.NextStageID = new SelectList(db.OMStages.OrderBy(x => x.StageValue), "StageID", "StageName");
ViewBag.PIPENO = new SelectList(db.PipeAls, "PIPENO", "PIPENO");
ViewBag.Status = new SelectList(db.ValueAddLists.Where(x => x.RefName == "PipeStatus"), "RefValue", "Description", process.Status);
return View(process);
}

Laxmidhar Sahoo · Answer

hi where db is defined

Suraj Kumar · Answer

Hello Raju, Good morning. As I am still seraching why entity framework sometimes doesn't give updated value? I was also facing same issue recently as I have to update remarks in table and sending into that remark into mail. I was trying to get that remark by id but it was giving null. I will post to you once find the solution why we don;t get value what we have updated?

Raju Fodse · Answer

Hello Suraj Good Morning! Your suggestion is acceptable but why my Entitiy Framework Conext not refreshing values. Where I am wrong.

Suraj Kumar · Answer

Hello Raju, As you are adding or updating something into table and need to get that updated value and check that value for putting condition. As you have already tried to get that updated value from linq query. I suggest you to get that updated value from stored procedure. First create a procedure as sample given below: CREATE PROCEDURE [dbo].[EP_GetHeaderId] -- Add the parameters for the stored procedure here @EH_EMP_CODE varchar (10), @EH_MONTH int , @EH_YEAR varchar (4) AS BEGIN -- SET NOCOUNT ON added to prevent extra result sets from -- interfering with SELECT statements. SET NOCOUNT ON ; -- Insert statements for procedure here SELECT * FROM ET_EXPENSE_HEAD WHERE EH_EMP_CODE = @EH_EMP_CODE and EH_MONTH = @EH_MONTH AND EH_YEAR=@EH_YEAR AND (EH_SUPR_REJECT_YN = 'N' OR EH_SUPR_REJECT_YN IS NULL ) END Now you need to import this sql procedure into the entity framework after importing it into the entity framework you can execute it to get that value. if (dtHeaderId.Count >= 1) { ViewBag.HeaderId = dtHeaderId[0].EH_SYS_ID; } else { ViewBag.HeaderId = 0; } Here suppose I have taken header id into the ViewBag but if your value is string or integer then you can declare variable for string or integer and assign value into that variable.

Raju Fodse · Answer

I googled for above issue I found I need to refresh my entity framework context. I try but not sucess. I am not getting any error but value retrives in MyTHK variable is old value again and again

Raju Fodse · Answer

Hi Suraj Can you give me some idea or example to complete my task?

Laxmidhar Sahoo · Answer

I think suraj is write

Suraj Kumar · Answer

Hello Raju, You can get updated value from table by writing a stored procedure and importing it into the Entity Framework and running after the previous id which you have updated into another table. You need to pass that value in newly created stored procedure.

Raju Fodse · Answer

I task is I want to comapre Thickness value with hardcoded parameters and set value for 'MPP' filed. This Thickness filed is in other table and I want to call that filed to comapre with value and then save record. if (process.PipeAl.Order.THK > 1) { process.MPP = 10; }

Laxmidhar Sahoo · Answer

I think the parameter you pass process is not intialised when you call again.

Raju Fodse · Answer

Yes, My linq context not refreshing and it takes old values always.

Laxmidhar Sahoo · Answer

hi your code looks ok. But when called it the process may not refereshed

Raju Fodse · Answer

I want Value in Line no 15. ( process.PipeAl.Order.THK ). The code you suggest I already done but my task is to retrive value of Thickness Filed which is in Order Table. More Information : I try Linq it works but every time it takes old value and i am unable to refresh context I try this but faild any idea if any body have. LPDBContext newdb = new LPDBContext(); //using (LPDBContext newdb = new LPDBContext()) var objectContext = ((IObjectContextAdapter)newdb).ObjectContext; var MyThk = (from ot in newdb.Processes join v in newdb.PipeAls on ot.PIPENO equals v.PIPENO join c in newdb.Orders on v.OrderSYSID equals c.OrderSYSID select c.THK).FirstOrDefault().GetValueOrDefault(); objectContext.Refresh(RefreshMode.StoreWins, MyThk); if (checkme.Count > 0) { ModelState.AddModelError( "PIPENO" , "You are trying Duplicate Pipe Entry" ); } if (ModelState.IsValid) { //if ((MyThk >= 6 && MyThk = 1 && MyDia = 5 && MyLength if (MyThk>10) { process.MPP = 80; process.TPCPL = 3; } else { process.MPP = 10; } process.CuttingSpeed = (process.ActualMeter*1000)/process.CuttingTime; newdb.Processes.Add(process); newdb.SaveChanges(); return RedirectToAction( "IndexP3" ); }

Laxmidhar Sahoo · Answer

try it var SID = process.StageID; var PNP = process.PIPENO; var STS = process.Status; var checkme = (from x in db.Processes where x.StageID == SID && x.PIPENO == PNP x.Status == STS && x.Status == "OK" select x).ToList();