Does not update a record in MVC using Linq to SQL.

Ujjval Shukla

10y830.NET

Hi friends i am new in MVC,

I'm working on an MVC application with LINQ TO SQL ORM.While update operation it show the error-

Object reference not set to an instance of an object.
 
Below is the Action to Update
 
public ActionResult disUpdate(Employee eid)
        {
            if (ModelState.IsValid)
            {
                
                
                 Empmaster ed1 = db.Empmasters.Where(u => u.Emp_Id == eid.EmployeeID).SingleOrDefault();
                
                 
                ed1.Category = eid.Category;
                 ed1.Emp_Name = eid.ename;
                 ed1.Father_Husband_Name = eid.fname;
                 ed1.departmet = eid.dept;
                 ed1.designation = eid.des;
                 ed1.doj = eid.doj;
                 ed1.dob = eid.dob;
                 ed1.sex = eid.sex;
                 ed1.mstatus = eid.mstatus;
                 ed1.address = eid.address;
                 ed1.status = Convert.ToChar(eid.status);
                db.SubmitChanges();
                return View("Index");
            }
            else
            {
 
                return View();
            }
        
        }

6 Replies

Know the answer? Post it — somebody with the same question will find it here.

Ujjval Shukla10y ago
Thanks Manas,

But i got the solution.i used another parameter for EmployeeId. It should be look like this to filter the record-

public ActionResult disUpdate(int? id,Employee eid)
{
if (ModelState.IsValid)
{
Empmaster ed1 = db.Empmasters.FirstOrDefault(u => u.Emp_Id == id);
ed1.Category = eid.Category;
ed1.Emp_Name = eid.ename;
ed1.Father_Husband_Name = eid.fname;
ed1.departmet = eid.dept;
ed1.designation = eid.des;
ed1.doj = eid.doj;
ed1.dob = eid.dob;
ed1.sex = eid.sex;
ed1.mstatus = eid.mstatus;
ed1.address = eid.address;
ed1.status = Convert.ToChar(eid.status);
db.SubmitChanges();
return RedirectToAction("Index");
}
else
{
return View();
}

}

it worked for me.

Thanks.
0
Ujjval Shukla10y ago
Question is not resolved.problem is still there.It show the same error.When i used Employeename instead of Employeeid in where condition it works fine and update data in database.Why it happens.
0
Ujjval Shukla10y ago
My table data is OK.When i display data on index ActionResult it show data.From this page when i click on Edit link it show data but it shows the employeeid=0 instead of actual ID like(1,2..etc.).Dont know why itake 0.EmployeeId column is Primary key of int datatype.
0
Manas Mohapatra10y ago
It may be due to following:

1. Make sure that you are filtering correct employee id.
2. Make sure that your table has proper data with respect to employee data. Cross check connection string is correct one.
0
Ujjval Shukla10y ago
Hi Manas Thanks for reply,

Yes, the object of Empmaster table is Null.Thats why it show the error.But i don't know how to resolve it.I have checked it may times.
0
Manas Mohapatra10y ago
Firstly make sure that you are getting correct value in (Employee eid). I believe that you are getting because you are using ModelState.IsValid property. Just cross check it.

Secondly if you won't get any record from Empmasters table then object is null. And you are assigning value to null object, so it throws error. Try with below code:

if (ModelState.IsValid)
{

   Empmaster ed1 = db.Empmasters.Where(u => u.Emp_Id ==    eid.EmployeeID).SingleOrDefault();

   // Make sure ed1 is not Null
   if(ed1!= null)
   {
      ed1.Category = eid.Category;
      ed1.Emp_Name = eid.ename;
      ed1.Father_Husband_Name = eid.fname;
      ed1.designation = eid.des;
      ed1.status = Convert.ToChar(eid.status);
      db.SubmitChanges();
   }

   return View("Index");
}
else
{
   return View();
}
0